X=15. This is the Altitude theorem which is Altitude/Part = Altitude/Other part. In this question you would set up the proportion 9/X = X/25 and multiply cross products to get 225=X^2. Then you undo X^2 by doing the square route of 225 and then you get 15 as the final answer.
Answer:
2-1 feflect like your math teacher told you
F(x) = 4 - x^2
g(x) = 6x
(g - f)(x) = g(x) - f(x) = 6x - (4 - x^2) = 6x - 4 + x^2
(g - f)(3) = 6(3) - 4 + 3^2
