 GED Math Extra Prep: Value Substitution - dummies

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

1. What is the value of 6x – 3y2 when x = 12 and y = –5?

A. –153
B. 297
C. –3
D. 147

The next question is based on the following information. 2. Which of the following expresses in terms of p?

A. 0
B. 1
C. p–5
D. p

1. The correct answer is C.

Substitute the given values of x and y into the expression:

6x – 3y2 = 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.

2. The correct answer is B.

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