6-7 grade

[Math Tutor]

If the function f(x) = a.x.x, find out f(4) if f(-4) = 72

[Guest]

f(x) = a.x^2, and x^2=(-x)^2 for any real x => f(-x)=f(x) => f(-4)=f(4) => f(4) = 72
that's it