Chapter 5 - Section 5.1 - Introduction to Polynomials and Polynomial Functions - Exercise Set - Page 324: 14

$20$

RECALL: $f(a)$ represents the value of the function $f$ when $x=a$. Thus, $f(-2)$ represents the value of the function $f$ when $x=-2$. Substitute $-2$ to $x$ in the function $f$ to obtain: $f(-2) = (-2)^2-5(-2)+6 \\f(-2)=4-(-10)+6 \\f(-2)=4+10+6 \\f(-2)=20$