SAT · Passport to Advanced Math · Rational expressions and equations
Question sat-q-00098
Easy Multiple choice No calculator
The question
For what value of x is the expression (x + 2) / (x − 2) undefined?
- 2
- 2
- -2
- -2
Show answer & worked solution
Answer: 2
Worked solution. A rational expression is undefined when its denominator equals zero. Set x − 2 = 0, so x = 2.
Why each wrong choice is wrong. Sign-flip distractors are everywhere here. Students who see (x − 2) and answer −2 are extracting the wrong root.
Test-day tactic. Restricted values come from setting the denominator equal to zero, then solving — the numerator is irrelevant.
About this question type
A rational expression is a ratio of two polynomials. SAT items ask you to simplify, to identify restricted values where the denominator equals zero, to add or subtract two rational expressions, or to solve a rational equation by clearing denominators.
You will see a question shaped like this one on roughly every other official SAT form, typically at an early position in the section, where missing them carries an outsize penalty because the curve assumes everyone in your band gets them right. Treat any miss in this subtopic as a signal to drill the subtopic page before you do another full practice test.