# Use Solve for two Functions to find 1 common Variable

I have 2 functions that look like this:

F[t_,d_]:= 10+t+2d

G[t_,d_]:= 5+t+d

I'd like to solve this in such a way to know for which t both Function have the Same value.

I assume that this won't be a single solution, rather a table/list full of values for different d's. But I can't get even that.

Thanks in advance for any help (:

• FindInstance[F[t, d] == G[t, d], {t, d}] – Lotus Aug 6 '18 at 9:48

F[t_, d_] := 10 + t + 2 d
G[t_, d_] := 5 + t + d

Plot3D[{F[t, d], G[t, d]}, {t, 0, 10}, {d, -10, 5},
AxesLabel -> (Style[#, 14, Bold] & /@ {t, d})]


Consequently, the functions are equal for any t provided that d is

Solve[F[t, d] == G[t, d], d][[1]]

(* {d -> -5} *)