function arithmetic problem!

Question

suppose that f(x) = √x and that f(g(t)) = √t²+8. what must be the formula for g(t)?

note: (the x and t²+8 are both entirely under the square root, sorry its unclear)

Answer 1

g(t) = t^2 + 8

f(g(t)) is found by replacing the x in f(x) with g(t) to get sqr(g(t)) = sqr(t^2+8). g(t) = t^2+8