### Home > CCA > Chapter A > Lesson A.1.2 > ProblemA-18

A-18.

Remember that one meaning of the word “evaluate” is to replace a variable with a number and to calculate the result. For example, evaluating the expression $x^2$ when $x=−2$ gives the solution$(−2)^2=4$.

Evaluate the expressions below for the given values.

1.  $−4d+3\text{ if }d=−1$

Substitute $−1$ for $d$.

$−4(−1)+3$

Simplify the terms and combine them.

$4+3=7$

$7$

1.  $k − m \text{ if } k = 4 \text{ and } m = −10$

Follow the steps in part (a).

Put everything you substituted inside parentheses so you do not lose your negative signs.

$(4)−(−10)$

1.  $\frac { t } { w }\text{ if } t = 6 \text{ and } w = −3$

Follow the steps in part (a).

$−2$

1.  $x^2+y^2\text{ if }x=7\text{ and }y=5$

Follow the steps in part (a).