# GED Math Extra Prep: Value Substitution

Value substitution questions on the GED Math test are fairly straightforward: they ask you to substitute actual numbers for variables in an expression and find the answer. The important thing to remember here is order of operations, or PEMDAS.

## Practice Questions

- What is the value of 6
*x*– 3*y*^{2}when*x*= 12 and*y*= –5?**A.**–153

**B.**297

**C.**–3

**D.**147*The next question is based on the following information.* - Which of the following expresses
in terms of

*p?***A.**0

**B.**1

**C.***p*^{–5}

**D.***p*

## Answers and Explanations

- The correct answer is C.
Substitute the given values of

*x*and*y*into the expression:6

*x*– 3*y*^{2}= 6(12) – 3(–5)^{2}Then use the correct order of operations to simplify: Remember PEMDAS — (Parentheses, then Exponents, then Multiplication and Division, and then Addition and Subtraction). So first evaluate the exponent, then perform the multiplication, and finally perform the subtraction:

Hence, Choice (C) is correct.

- The correct answer is B.
Any expression to the power zero equals 1. Hence, the correct answer is Choice (B).