### Home > PC3 > Chapter 1 > Lesson 1.1.2 > Problem1-15

1-15.

Let $f(x)=2x^2-3$. Evaluate:

1. $f(4)$

Substitute $4$ for every $x$ in the function.

$f(4)=2(4)^2-3$

1. $f(-5)$

Use ( ) when substituting to avoid errors.

$f(−5)=2(−5)^2−3$