Practice Math Questions for Praxis: Simplifying an Algebraic Expression

Some algebraic expressions on the Praxis Core exam may look intimidating, and you may even want to give up on them and move on. As you'll see in the following practice questions, though, you can use some simple techniques—like factoring and combining like terms—to solve them.

Practice questions

1. Which of the following is the simplified form of the expression 8x²y – 5xy² + 12xy² – 3x²y?

   A. 5x²y² + 7x²y B. 3x²y + 9xy² C. 5x²y + 7xy² D. 5x²y² + 7x²y² E. 7x²y² + 5x²y²

2. Which of the following is the simplified form of

   

Answers and explanations

1. The correct answer is Choice (C). You can combine the like terms to simplify the expression. Like terms have the same variables, and each variable has the same exponent in each of the like terms.

   To combine like terms, add their coefficients; the variable-and-exponent combinations that the terms have in common go to the right of the new coefficients:

   

2. The correct answer is Choice (D).
   Factor the numerator and denominator. Then cancel any expression that's a factor of the numerator and denominator.