Question

F(x) = -x2 - 9x
Find f(-2)

Answer 1

f(-2)=14

Explanation:

`f(x) = -x^2 - 9x\\\\f(-2) = -(-2)^2-9(-2)\\\\\mathrm{Follow\:the\:PEMDAS\:order\:of\:operations}\\\\\mathrm{Calculate\:exponents}\:\left(-2\right)^2\::\quad 4\\=-4-9\left(-2\right)\\\\\mathrm{Multiply\:and\:divide\:\left(left\:to\:right\right)}\:9\left(-2\right)\::\quad -18\\\\=-4-\left(-18\right)\\\\\mathrm{Add\:and\:subtract\:\left(left\:to\:right\right)}\:-4-\left(-18\right)\:\\f(-2):\quad 14`

Answer 2

22

Explanation:

replace -2 for every in the equation:

-(-2)x2-9x-2=22