### Home > CC3 > Chapter 2 > Lesson 2.1.1 > Problem 2-9

2-9.

One meaning of the word evaluate is to find the value of an expression. To evaluate, replace a variable with a number and calculate the result. For example, when you are asked to evaluate the expression 4*x* − 2 when *x* = −7, you would put −7 in place of the variable and calculate: 4 · (−7) − 2 = −30.

Evaluate the expressions below for the given values of *x* and *y*. Homework Help ✎

Rewrite the expression with the number in place of the variable and simplify if possible.

+ 9 if

*x*= 311

8

*x*− 3 +*y*if*x*= 2 and*y*= 18(2) − 3 + (1)

Try evaluating this one on your own.

2

*xy*if*x*= 5 and*y*= −32(5)(−3) = 10(−3)

−30

2

*x*^{2}−*y*if*x*= 3 and*y*= 82(3)

^{2}− (8)Try evaluating this one on your own. You have been given a head start.