The function f(x) varies directly with x^2, and f(x) = 75, when x = 5, What is the value of f(4)?
f(x) = kx^2 for constant k
f(5) = 75 = 5^2k
Solve for K
75 = 5^2k
75 = 25k
Divide by 25
k = 3
Equation: f(x) = 3x^2
f(4) = 3(4)^2
f(4) = 3(16)
f(4) = 48
So, f(4) = 3.4^2 = 48
Your answer would be: Letter Choice (C) (48)
Hope that helps!!!!
