Question

If f(x) =15x 2 + 10x, find f(-1) Anyone know the answer?

Answer 1

I'm assuming the given function is f(x) = 15x^2 + 10x.

If so, then,

f(x) = 15x^2 + 10x
f(x) = 15*(x)^2 + 10*(x)
f(-1) = 15*(-1)^2 + 10*(-1) ... note how x is replaced with -1
f(-1) = 15*(1) + 10*(-1)
f(-1) = 15 - 10
f(-1) = 5

Therefore the answer is 5