Question

Given f(x) = –x2 + 10x – 16 and g(x) = |11 – 2x2 |, find 2•f(9) – g(–5)

Answer 1

The answer is -53.

Explanation

Given functions are:   $f(x)= -x^2 +10x-16$ and  $g(x)= |11-2x^2|$

We need find the value of:   $2*f(9)-g(-5)$

For finding the value of $f(9)$, we will plug $x=9$ into the given function $f(x)$. So.....

$f(9)= -(9)^2+10(9)-16 = -81+90-16 = -7$

Now for finding the value of $g(-5)$, we will plug $x=-5$ into the given function $g(x)$. So.......

$g(-5)= |11-2(-5)^2| = |11-50|=|-39|=39$

Thus,  $2*f(9)-g(-5)=2(-7)-(39)= -14-39= -53$