Practice Math Questions for Praxis: Solving Expressions with Given Values - dummies

# Practice Math Questions for Praxis: Solving Expressions with Given Values

Some questions on the Praxis Core exam involve a simple plug-and-play approach, where you solve an expression by substituting given values for the variables. Sounds easy, right?

Well, yes and no: as you’ll see in the following practice questions, you still need to watch out for double negatives and you have to know your order of operations.

## Practice questions

1. What is the value of this expression if x = 1, y = –5, z = 8?

7x – 5y + 4z

A. –8
B. 103
C. 64
D. 36
E. –71

2. What is the value of this expression if k = –7, m = –10, and n = 11?

## Answers and explanations

1. The correct answer is Choice (C).
Substitute each variable value in for its corresponding variable. Then simplify the result.

2. The correct answer is Choice (C).
You can substitute each variable value in for its corresponding variable and then simplify the resulting rational expression: