I'm currently trying to solve this system of two ode's and can't seem to be able to solve them. I am new to coding, so I don't know where I could have done a mistake. I'm attaching the code which I thought would give a answer, but have gotten an error which I don't understand. What it is in reference too. Please, if you could guide me in the right direction, I would really appreciate it. Also, if it is not to much to ask for any hints on plotting x and y vs time. Thank you for you help.
equation1 := {x'[t] ==
1/(1 + (1/25) (y[t] - (2 y[t])/(1 + sqrt[1 + 1600 y[t]]))^2) -
0.1 x[t],
y'[t] ==
0.5 x[t] - (((20 y[t])/(1 + sqrt[1 + 1600 y[t]]) +
0.03 y[t])/(0.05 + y[t])) - 0.1 y[t], x[0] == 0, y[0] == 0};
DSolve[equation1, {x[t], y[t]}, t]
During evaluation, DSolve::ivar: 5 is not a valid variable. >>
(* DSolve[{0 == -0.1 5[t] + 1/(
1 + 1/25 (15[t] - (2 15[t])/(1 + sqrt[1 + 1600 15[t]]))^2),
0 == 0.5 5[t] - 0.1 15[t] - (
0.03 15[t] + (20 15[t])/(1 + sqrt[1 + 1600 15[t]]))/(
0.05 + 15[t]), 5[0] == 0, 15[0] == 0}, {5[t], 15[t]}, t] *)