# Solving a large equation set

ClearAll[Equations, Unknows]
Equations = {c1bXZ[6] - (Sqrt[3]*c1bYZ[1])/2 + c1sStr[1]/2 +
c1sStr[3] == (-1)*RX[1],
c1bXZ[4] + (Sqrt[3]*c1bYZ[1])/2 - (Sqrt[3]*c1bYZ[5])/2 +
0.00005061454828623123*c1bYZ[8] -
0.00005061454828613165*c1bYZ[9] - c1sStr[1]/2 + c1sStr[5]/2 -
0.9999999987190837*c1sStr[8] +
0.9999999987190837*c1sStr[9] == (-1)*0, -c1bXZ[4] + c1sStr[2] -
c1sStr[3] == (-1)*0, -c1bXZ[7] + (Sqrt[3]*c1bYZ[5])/2 -
c1sStr[2] - c1sStr[5]/2 == (-1)*RX[4], -c1bXZ[6] -
0.00005061454828623123*c1bYZ[8] +
0.9999999987190837*c1sStr[8] == (-1)*0,
c1bXZ[7] + 0.00005061454828613165*c1bYZ[9] -
0.9999999987190837*c1sStr[9] == (-1)*0,
c1bYZ[1]/2 + c1bYZ[3] + (Sqrt[3]*c1sStr[1])/2 + c1sStr[6] == (-1)*
RY[1], -c1bYZ[1]/2 - c1bYZ[5]/2 - 0.9999999987190837*c1bYZ[8] -
0.9999999987190837*c1bYZ[9] - (Sqrt[3]*c1sStr[1])/2 -
c1sStr[4] - (Sqrt[3]*c1sStr[5])/2 -
0.00005061454828623123*c1sStr[8] -
0.00005061454828623123*c1sStr[9] == (-1)*F,
c1bYZ[2] - c1bYZ[3] + c1sStr[4] == (-1)*0, -c1bYZ[2] +
c1bYZ[5]/2 + (Sqrt[3]*c1sStr[5])/2 + c1sStr[7] == (-1)*RY[4],
0.9999999987190837*c1bYZ[8] - c1sStr[6] +
0.00005061454828623123*c1sStr[8] == (-1)*0,
0.9999999987190837*c1bYZ[9] - c1sStr[7] +
0.00005061454828623123*c1sStr[9] == (-1)*0,
c1bXZ[1] + c1bXZ[3] - c1bYZ[6] == (-1)*RZ[1], -c1bXZ[1] +
c1bXZ[5] - c1bXZ[8] + c1bXZ[9] + c1bYZ[4] == (-1)*0,
c1bXZ[2] - c1bXZ[3] - c1bYZ[4] == (-1)*0, -c1bXZ[2] - c1bXZ[5] -
c1bYZ[7] == (-1)*RZ[4],
c1bXZ[8] + c1bYZ[6] == (-1)*0, -c1bXZ[9] +
c1bYZ[7] == (-1)*0, -c1tTor[1]/2 -
c1tTor[3] - (Sqrt[3]*(c1bXZ[1] + c2bXZ[1]))/2 - c2bYZ[6] ==
MX[1], c1tTor[1]/2 - c1tTor[5]/2 + 0.9999999987190837*c1tTor[8] -
0.9999999987190837*c1tTor[9] + (Sqrt[3]*c2bXZ[1])/
2 - (Sqrt[3]*c2bXZ[5])/2 + 0.00005061454828623123*c2bXZ[8] -
0.00005061454828613165*c2bXZ[9] - c2bYZ[4] ==
0, (433*c1bYZ[4])/500 - c1tTor[2] + c1tTor[3] + c2bYZ[4] ==
0, (433*c1bYZ[7])/500 + c1tTor[2] +
c1tTor[5]/2 + (Sqrt[3]*(c1bXZ[5] + c2bXZ[5]))/2 + c2bYZ[7] ==
MX[4], (433*c1bYZ[6])/500 - 0.9999999987190837*c1tTor[8] -
0.00005061454828623123*(c1bXZ[8]/2 + c2bXZ[8]) + c2bYZ[6] == 0,
0.9999999987190837*c1tTor[9] +
0.00005061454828613165*(c1bXZ[9]/2 + c2bXZ[9]) - c2bYZ[7] == 0,
c1bXZ[3]/2 - (Sqrt[3]*c1tTor[1])/2 -
c1tTor[6] + (c1bXZ[1] + c2bXZ[1])/2 + c2bXZ[3] ==
MY[1], (Sqrt[3]*c1tTor[1])/2 +
c1tTor[4] + (Sqrt[3]*c1tTor[5])/2 +
0.00005061454828623123*c1tTor[8] +
0.00005061454828623123*c1tTor[9] - c2bXZ[1]/2 - c2bXZ[5]/2 -
0.9999999987190837*c2bXZ[8] - 0.9999999987190837*c2bXZ[9] == 0,
c1bXZ[2]/2 - c1tTor[4] + c2bXZ[2] - c2bXZ[3] ==
0, -(Sqrt[3]*c1tTor[5])/2 - c1tTor[7] -
c2bXZ[2] + (c1bXZ[5] + c2bXZ[5])/2 == MY[4],
c1tTor[6] - 0.00005061454828623123*c1tTor[8] +
0.9999999987190837*(c1bXZ[8]/2 + c2bXZ[8]) == 0,
c1tTor[7] - 0.00005061454828623123*c1tTor[9] +
0.9999999987190837*(c1bXZ[9]/2 + c2bXZ[9]) ==
0, -c1bYZ[1] - c1bYZ[3]/2 - c2bXZ[6] - c2bYZ[1] - c2bYZ[3] == 0,
c2bXZ[4] + c2bYZ[1] - c2bYZ[5] + c2bYZ[8] - c2bYZ[9] ==
0, (-433*c1bXZ[4])/500 - c1bYZ[2]/2 - c2bXZ[4] - c2bYZ[2] +
c2bYZ[3] ==
0, (-433*c1bXZ[7])/500 + c1bYZ[5] - c2bXZ[7] + c2bYZ[2] +
c2bYZ[5] ==
0, (433*c1bXZ[6])/500 - c1bYZ[8]/2 + c2bXZ[6] - c2bYZ[8] == 0,
c1bYZ[9]/2 + c2bXZ[7] + c2bYZ[9] ==
0, -c1sStr[3]/4000000000 + (-c1sStr[1]/2000000000 - c2sStr[1])/2 -
c2sStr[3] -
c4bXZ[6] - (Sqrt[
3]*((c1bYZ[1] + 3*c2bYZ[1] + 2400000*c3bYZ[1])/2400000 +
c4bYZ[1]))/2 ==
0, -c2sStr[2] + (c1sStr[5]/2000000000 + c2sStr[5])/
2 - (433*((433*((433*c1bXZ[7])/500 + 3*c2bXZ[7]))/500 +
2400000*c3bXZ[7]))/1200000000 -
c4bXZ[7] + (Sqrt[
3]*((c1bYZ[5] + 3*c2bYZ[5] + 2400000*c3bYZ[5])/2400000 +
c4bYZ[5]))/2 ==
0, -(Sqrt[3]*(c1sStr[1]/2000000000 + c2sStr[1]))/2 +
c2sStr[6] + ((c1bYZ[3]/2 + 3*c2bYZ[3])/2 + 2400000*c3bYZ[3])/
4800000 + ((c1bYZ[1] + 3*c2bYZ[1] + 2400000*c3bYZ[1])/2400000 +
c4bYZ[1])/2 + c4bYZ[3] ==
0, (-433*c1sStr[7])/
1000000000000 - (Sqrt[3]*(c1sStr[5]/2000000000 + c2sStr[5]))/2 -
c2sStr[7] +
c4bYZ[2] + ((c1bYZ[5] + 3*c2bYZ[5] + 2400000*c3bYZ[5])/2400000 +
c4bYZ[5])/2 ==
0, (c1bXZ[1] + 3*c2bXZ[1] + 2400000*c3bXZ[1])/
2400000 + ((c1bXZ[3]/2 + 3*c2bXZ[3])/2 + 2400000*c3bXZ[3])/
4800000 + c4bXZ[1] + c4bXZ[3] + c4bYZ[6] ==
0, (-c1bXZ[5] - 3*c2bXZ[5] - 2400000*c3bXZ[5])/
2400000 - (433*((433*((433*c1bYZ[7])/500 + 3*c2bYZ[7]))/500 +
2400000*c3bYZ[7]))/1200000000 + c4bXZ[2] - c4bXZ[5] -
c4bYZ[7] ==
0, (-c1sStr[1]/2000000000 - c2sStr[1])/
2 - (Sqrt[
3]*((c1bYZ[1] + 3*c2bYZ[1] + 2400000*c3bYZ[1])/2400000 +
c4bYZ[1]))/2 == -c1sStr[3]/4000000000 -
c2sStr[3], -c1sStr[3]/4000000000 -
c2sStr[3] == -c4bXZ[6], -c2sStr[1]/2 - (Sqrt[3]*c4bYZ[1])/
2 == -c4bXZ[4], -c4bXZ[4] == c2sStr[5]/2 + (Sqrt[3]*c4bYZ[5])/2,
c2sStr[5]/2 + (Sqrt[3]*c4bYZ[5])/2 == -0.9999999987190837*
c2sStr[8] -
0.00005061454828623123*c4bYZ[8], -0.9999999987190837*c2sStr[8] -
0.00005061454828623123*c4bYZ[8] ==
0.9999999987190837*c2sStr[9] +
0.00005061454828613165*c4bYZ[9], -c1sStr[2]/4000000000 -
c2sStr[2] == -c2sStr[3], -c2sStr[
3] == (-433*((433*((433*c1bXZ[4])/500 + 3*c2bXZ[4]))/500 +
2400000*c3bXZ[4]))/1200000000 -
c4bXZ[4], -c2sStr[2] == (c1sStr[5]/2000000000 + c2sStr[5])/
2 + (Sqrt[
3]*((c1bYZ[5] + 3*c2bYZ[5] + 2400000*c3bYZ[5])/2400000 +
c4bYZ[5]))/2, (c1sStr[5]/2000000000 + c2sStr[5])/
2 + (Sqrt[
3]*((c1bYZ[5] + 3*c2bYZ[5] + 2400000*c3bYZ[5])/2400000 +
c4bYZ[5]))/
2 == (-433*((433*((433*c1bXZ[7])/500 + 3*c2bXZ[7]))/500 +
2400000*c3bXZ[7]))/1200000000 -
c4bXZ[7], (-433*((433*((433*c1bXZ[6])/500 + 3*c2bXZ[6]))/500 +
2400000*c3bXZ[6]))/1200000000 -
c4bXZ[6] == -0.9999999987190837*(c1sStr[8]/4000000000 +
c2sStr[8]) -
0.00005061454828623123*(((c1bYZ[8]/2 + 3*c2bYZ[8])/2 +
2400000*c3bYZ[8])/4800000 + c4bYZ[8]), -c4bXZ[7] ==
0.9999999987190837*(c1sStr[9]/4000000000 + c2sStr[9]) +
0.00005061454828613165*(((c1bYZ[9]/2 + 3*c2bYZ[9])/2 +
2400000*c3bYZ[9])/4800000 +
c4bYZ[9]), -(Sqrt[3]*(c1sStr[1]/2000000000 + c2sStr[1]))/
2 + ((c1bYZ[1] + 3*c2bYZ[1] + 2400000*c3bYZ[1])/2400000 +
c4bYZ[1])/
2 == ((c1bYZ[3]/2 + 3*c2bYZ[3])/2 + 2400000*c3bYZ[3])/4800000 +
c4bYZ[3], ((c1bYZ[3]/2 + 3*c2bYZ[3])/2 + 2400000*c3bYZ[3])/
4800000 + c4bYZ[3] ==
c2sStr[6], -(Sqrt[3]*c2sStr[1])/2 +
c4bYZ[1]/2 == -c2sStr[4], -c2sStr[4] == -(Sqrt[3]*c2sStr[5])/2 +
c4bYZ[5]/2, -(Sqrt[3]*c2sStr[5])/2 +
c4bYZ[5]/2 == -0.00005061454828623123*c2sStr[8] +
0.9999999987190837*c4bYZ[8], -0.00005061454828623123*c2sStr[8] +
0.9999999987190837*c4bYZ[8] == -0.00005061454828623123*
c2sStr[9] +
0.9999999987190837*
c4bYZ[9], ((c1bYZ[2]/2 + 3*c2bYZ[2])/2 + 2400000*c3bYZ[2])/
4800000 + c4bYZ[2] == c4bYZ[3],
c4bYZ[3] == (-433*c1sStr[4])/1000000000000 - c2sStr[4],
c4bYZ[2] == -(Sqrt[3]*(c1sStr[5]/2000000000 + c2sStr[5]))/
2 + ((c1bYZ[5] + 3*c2bYZ[5] + 2400000*c3bYZ[5])/2400000 +
c4bYZ[5])/2, -(Sqrt[3]*(c1sStr[5]/2000000000 + c2sStr[5]))/
2 + ((c1bYZ[5] + 3*c2bYZ[5] + 2400000*c3bYZ[5])/2400000 +
c4bYZ[5])/2 == (-433*c1sStr[7])/1000000000000 -
c2sStr[7], (433*c1sStr[6])/1000000000000 +
c2sStr[6] == -0.00005061454828623123*(c1sStr[8]/4000000000 +
c2sStr[8]) +
0.9999999987190837*(((c1bYZ[8]/2 + 3*c2bYZ[8])/2 +
2400000*c3bYZ[8])/4800000 + c4bYZ[8]), -c2sStr[
7] == -0.00005061454828623123*(c1sStr[9]/4000000000 +
c2sStr[9]) +
0.9999999987190837*(((c1bYZ[9]/2 + 3*c2bYZ[9])/2 +
2400000*c3bYZ[9])/4800000 + c4bYZ[9]), (c1bXZ[1] +
3*c2bXZ[1] + 2400000*c3bXZ[1])/2400000 +
c4bXZ[1] == ((c1bXZ[3]/2 + 3*c2bXZ[3])/2 + 2400000*c3bXZ[3])/
4800000 +
c4bXZ[3], ((c1bXZ[3]/2 + 3*c2bXZ[3])/2 + 2400000*c3bXZ[3])/
4800000 + c4bXZ[3] == c4bYZ[6],
c4bXZ[1] == -c4bYZ[4], -c4bYZ[4] == -c4bXZ[5], -c4bXZ[5] ==
c4bXZ[8],
c4bXZ[8] == -c4bXZ[
9], ((c1bXZ[2]/2 + 3*c2bXZ[2])/2 + 2400000*c3bXZ[2])/4800000 +
c4bXZ[2] == c4bXZ[3],
c4bXZ[3] == (-433*((433*((433*c1bYZ[4])/500 + 3*c2bYZ[4]))/500 +
2400000*c3bYZ[4]))/1200000000 - c4bYZ[4],
c4bXZ[2] == (-c1bXZ[5] - 3*c2bXZ[5] - 2400000*c3bXZ[5])/2400000 -
c4bXZ[5], (-c1bXZ[5] - 3*c2bXZ[5] - 2400000*c3bXZ[5])/2400000 -
c4bXZ[5] == (-433*((433*((433*c1bYZ[7])/500 + 3*c2bYZ[7]))/500 +
2400000*c3bYZ[7]))/1200000000 -
c4bYZ[7], (433*((433*((433*c1bYZ[6])/500 + 3*c2bYZ[6]))/500 +
2400000*c3bYZ[6]))/1200000000 +
c4bYZ[6] == ((c1bXZ[8]/2 + 3*c2bXZ[8])/2 + 2400000*c3bXZ[8])/
4800000 +
c4bXZ[8], -c4bYZ[
7] == ((-c1bXZ[9]/2 - 3*c2bXZ[9])/2 - 2400000*c3bXZ[9])/
4800000 -
c4bXZ[9], -c1tTor[3]/280000 + (-c1tTor[1]/140000 - c2tTor[1])/2 -
c2tTor[3] - (Sqrt[
3]*((c1bXZ[1] + 2*c2bXZ[1])/800000 + c3bXZ[1]))/2 +
c3bYZ[6] ==
0, (433*((433*c1bYZ[7])/500 + 2*c2bYZ[7]))/400000000 -
c2tTor[2] + (c1tTor[5]/140000 + c2tTor[5])/
2 + (Sqrt[3]*((c1bXZ[5] + 2*c2bXZ[5])/800000 + c3bXZ[5]))/2 +
c3bYZ[7] ==
0, (c1bXZ[3]/2 + 2*c2bXZ[3])/
1600000 - (Sqrt[3]*(c1tTor[1]/140000 + c2tTor[1]))/2 +
c2tTor[6] + ((c1bXZ[1] + 2*c2bXZ[1])/800000 + c3bXZ[1])/2 +
c3bXZ[3] ==
0, (-433*c1tTor[7])/
70000000 - (Sqrt[3]*(c1tTor[5]/140000 + c2tTor[5]))/2 -
c2tTor[7] +
c3bXZ[2] + ((c1bXZ[5] + 2*c2bXZ[5])/800000 + c3bXZ[5])/2 ==
0, (-c1tTor[1]/140000 - c2tTor[1])/
2 - (Sqrt[3]*((c1bXZ[1] + 2*c2bXZ[1])/800000 + c3bXZ[1]))/
2 == -c1tTor[3]/280000 - c2tTor[3], -c1tTor[3]/280000 -
c2tTor[3] == c3bYZ[6], -c2tTor[1]/2 - (Sqrt[3]*c3bXZ[1])/2 ==
c3bYZ[4], c3bYZ[4] == c2tTor[5]/2 + (Sqrt[3]*c3bXZ[5])/2,
c2tTor[5]/2 + (Sqrt[3]*c3bXZ[5])/2 == -0.9999999987190837*
c2tTor[8] -
0.00005061454828623123*c3bXZ[8], -0.9999999987190837*c2tTor[8] -
0.00005061454828623123*c3bXZ[8] ==
0.9999999987190837*c2tTor[9] +
0.00005061454828613165*c3bXZ[9], -c1tTor[2]/280000 -
c2tTor[2] == -c2tTor[3], -c2tTor[
3] == (433*((433*c1bYZ[4])/500 + 2*c2bYZ[4]))/400000000 +
c3bYZ[4], -c2tTor[2] == (c1tTor[5]/140000 + c2tTor[5])/
2 + (Sqrt[3]*((c1bXZ[5] + 2*c2bXZ[5])/800000 + c3bXZ[5]))/
2, (c1tTor[5]/140000 + c2tTor[5])/
2 + (Sqrt[3]*((c1bXZ[5] + 2*c2bXZ[5])/800000 + c3bXZ[5]))/
2 == (433*((433*c1bYZ[7])/500 + 2*c2bYZ[7]))/400000000 +
c3bYZ[7], (433*((433*c1bYZ[6])/500 + 2*c2bYZ[6]))/400000000 +
c3bYZ[6] == -0.9999999987190837*(c1tTor[8]/280000 + c2tTor[8]) -
0.00005061454828623123*((c1bXZ[8]/2 + 2*c2bXZ[8])/1600000 +
c3bXZ[8]),
c3bYZ[7] ==
0.9999999987190837*(c1tTor[9]/280000 + c2tTor[9]) +
0.00005061454828613165*((c1bXZ[9]/2 + 2*c2bXZ[9])/1600000 +
c3bXZ[9]), -(Sqrt[3]*(c1tTor[1]/140000 + c2tTor[1]))/
2 + ((c1bXZ[1] + 2*c2bXZ[1])/800000 + c3bXZ[1])/
2 == (c1bXZ[3]/2 + 2*c2bXZ[3])/1600000 +
c3bXZ[3], (c1bXZ[3]/2 + 2*c2bXZ[3])/1600000 + c3bXZ[3] ==
c2tTor[6], -(Sqrt[3]*c2tTor[1])/2 +
c3bXZ[1]/2 == -c2tTor[4], -c2tTor[4] == -(Sqrt[3]*c2tTor[5])/2 +
c3bXZ[5]/2, -(Sqrt[3]*c2tTor[5])/2 +
c3bXZ[5]/2 == -0.00005061454828623123*c2tTor[8] +
0.9999999987190837*c3bXZ[8], -0.00005061454828623123*c2tTor[8] +
0.9999999987190837*c3bXZ[8] == -0.00005061454828623123*
c2tTor[9] +
0.9999999987190837*c3bXZ[9], (c1bXZ[2]/2 + 2*c2bXZ[2])/1600000 +
c3bXZ[2] == c3bXZ[3],
c3bXZ[3] == (-433*c1tTor[4])/70000000 - c2tTor[4],
c3bXZ[2] == -(Sqrt[3]*(c1tTor[5]/140000 + c2tTor[5]))/
2 + ((c1bXZ[5] + 2*c2bXZ[5])/800000 + c3bXZ[5])/
2, -(Sqrt[3]*(c1tTor[5]/140000 + c2tTor[5]))/
2 + ((c1bXZ[5] + 2*c2bXZ[5])/800000 + c3bXZ[5])/
2 == (-433*c1tTor[7])/70000000 -
c2tTor[7], (433*c1tTor[6])/70000000 +
c2tTor[6] == -0.00005061454828623123*(c1tTor[8]/280000 +
c2tTor[8]) +
0.9999999987190837*((c1bXZ[8]/2 + 2*c2bXZ[8])/1600000 +
c3bXZ[8]), -c2tTor[
7] == -0.00005061454828623123*(c1tTor[9]/280000 + c2tTor[9]) +
0.9999999987190837*((c1bXZ[9]/2 + 2*c2bXZ[9])/1600000 +
c3bXZ[9]), (-c1bYZ[1] - 2*c2bYZ[1])/800000 -
c3bYZ[1] == (-c1bYZ[3]/2 - 2*c2bYZ[3])/1600000 -
c3bYZ[3], (-c1bYZ[3]/2 - 2*c2bYZ[3])/1600000 - c3bYZ[3] ==
c3bXZ[6], -c3bYZ[1] == -c3bXZ[4], -c3bXZ[4] == c3bYZ[5],
c3bYZ[5] == -c3bYZ[8], -c3bYZ[8] ==
c3bYZ[9], (-c1bYZ[2]/2 - 2*c2bYZ[2])/1600000 -
c3bYZ[2] == -c3bYZ[3], -c3bYZ[
3] == (-433*((433*c1bXZ[4])/500 + 2*c2bXZ[4]))/400000000 -
c3bXZ[4], -c3bYZ[2] == (c1bYZ[5] + 2*c2bYZ[5])/800000 +
c3bYZ[5], (c1bYZ[5] + 2*c2bYZ[5])/800000 +
c3bYZ[5] == (-433*((433*c1bXZ[7])/500 + 2*c2bXZ[7]))/400000000 -
c3bXZ[7], (433*((433*c1bXZ[6])/500 + 2*c2bXZ[6]))/400000000 +
c3bXZ[6] == (-c1bYZ[8]/2 - 2*c2bYZ[8])/1600000 -
c3bYZ[8], -c3bXZ[7] == (c1bYZ[9]/2 + 2*c2bYZ[9])/1600000 +
c3bYZ[9]};


And unknowns

Unknows = {c1bXZ[1], c1bXZ[2], c1bXZ[3], c1bXZ[4], c1bXZ[5], c1bXZ[6],
c1bXZ[7], c1bXZ[8], c1bXZ[9], c2bXZ[1], c2bXZ[2], c2bXZ[3],
c2bXZ[4], c2bXZ[5], c2bXZ[6], c2bXZ[7], c2bXZ[8], c2bXZ[9],
c3bXZ[1], c3bXZ[2], c3bXZ[3], c3bXZ[4], c3bXZ[5], c3bXZ[6],
c3bXZ[7], c3bXZ[8], c3bXZ[9], c4bXZ[1], c4bXZ[2], c4bXZ[3],
c4bXZ[4], c4bXZ[5], c4bXZ[6], c4bXZ[7], c4bXZ[8], c4bXZ[9],
c1bYZ[1], c1bYZ[2], c1bYZ[3], c1bYZ[4], c1bYZ[5], c1bYZ[6],
c1bYZ[7], c1bYZ[8], c1bYZ[9], c2bYZ[1], c2bYZ[2], c2bYZ[3],
c2bYZ[4], c2bYZ[5], c2bYZ[6], c2bYZ[7], c2bYZ[8], c2bYZ[9],
c3bYZ[1], c3bYZ[2], c3bYZ[3], c3bYZ[4], c3bYZ[5], c3bYZ[6],
c3bYZ[7], c3bYZ[8], c3bYZ[9], c4bYZ[1], c4bYZ[2], c4bYZ[3],
c4bYZ[4], c4bYZ[5], c4bYZ[6], c4bYZ[7], c4bYZ[8], c4bYZ[9],
c1sStr[1], c1sStr[2], c1sStr[3], c1sStr[4], c1sStr[5], c1sStr[6],
c1sStr[7], c1sStr[8], c1sStr[9], c2sStr[1], c2sStr[2], c2sStr[3],
c2sStr[4], c2sStr[5], c2sStr[6], c2sStr[7], c2sStr[8], c2sStr[9],
c1tTor[1], c1tTor[2], c1tTor[3], c1tTor[4], c1tTor[5], c1tTor[6],
c1tTor[7], c1tTor[8], c1tTor[9], c2tTor[1], c2tTor[2], c2tTor[3],
c2tTor[4], c2tTor[5], c2tTor[6], c2tTor[7], c2tTor[8], c2tTor[9],
RX[1], RY[1], RZ[1], RX[4], RY[4], RZ[4], MX[1], MY[1], MX[4],
MY[4]};


Explain please why I can not to solve this set?

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It consists of =F= and can not be solved by NSolve. It requires symbolic notation solution. – Siarhei A Arlou Nov 29 '12 at 12:33
Isn't this a duplicate of mathematica.stackexchange.com/questions/15360? – whuber Nov 29 '12 at 17:28

Firstly convert the equations to matrix/vector form (i.e. $m_1.x=-m_0$).

{m0, m1} = CoefficientArrays[Equations, Unknows]


Then compute the (symbolic) solution.

soln = LinearSolve[m1, -m0] // Chop[#, 10^-6] &


I have chopped parts of the solution that are small, but you don't have to do this.

Verify that the solution is correct.

m1.soln + m0 // Chop[#, 10^-6] &

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Thank you, Stephen Luttrell. But what the way to provide back substitution. In case of traditional approach I'v used a phrase ResultSubs=Unknows/.Result. I will be glad to share results and real tasks description it concerns to. – Siarhei A Arlou Nov 29 '12 at 18:50
Is this correct For[i = 1, i <= Length[soln], i++, Unknows[[i]] = soln[[i]]; Print[Unknows[[i]]]] or it exists more elegant way? – Siarhei A Arlou Nov 29 '12 at 19:07
Conclusion. Symbolic calculations are very slow for real important engineering tasks in structural analysis. Only very simple tasks can be solved with symbolic data. – Siarhei A Arlou Nov 29 '12 at 21:57
@Siarhei A Arlou Depends on the symbolic computations, how they are done, how large is the result, ... – Daniel Lichtblau Nov 29 '12 at 22:40
@Daniel 10-30 beams-rods with some symbolic data is reality. Just tested. It requires algorithm optimization. I will do it in future for guaranteed partially (or even full) symbolic solution. Thank for support. If you have an interest to take a look on Mathematica power in structural mechanics timo 32 bit Win (32 bit Win) or timo 64 bit Win Installation instructions are included. – Siarhei A Arlou Nov 29 '12 at 23:21