F(x)=5x-4 and g(x)=x2 , what is (gof)(2)?

Question

F(x)=5x-4 and g(x)=x² , what is (g^of)(2)?

Answer 1

Hi Courniya.

Let's understand that (gof)(x) is shorthand for g(f(x)). That means replace each x in the function g by f(x).

Now g(x) = x^2, so, replacing x by f(x), we get (gof)(x) = (5x - 4)^2

That's all!

For extra credit, let's try (fog)(x) = f(g(x)) = 5 (x^2) - 4. [Replace every x in f(x) by g(x) = x^2]