Answer:
f(g(x))=3x^2-30x+75
Explanation:
We want to find the value of f(x) when x is equal to g(x)
So we can substitute the value of g(x) into the f(x) equation
f(g(x))= 3(5-x)^2
f(g(x))= 3(25-10x+x^2)
f(g(x))=3x^2-30x+75
Completely simplified version: 3(x-5)^2