SAT Math Multiple Choice Question 893: Answer and Explanation
8. For which values of x is the expressionundefined?
- A. -2
- B. -2, 5
- C. 0, -2, 5
- D. 0, 2, -5
Correct Answer: C
Category: Passport to Advanced Math / Exponents
Strategic Advice: An expression (or equation) is undefined for any value or values of the variable that result in a denominator equal to 0 or a negative quantity inside a square root. Having the expression already written in factored form makes finding these values very straightforward.
Getting to the Answer: There are three distinct factors in the denominator of the expression, so set each factor equal to 0, and solve for x:
The expression is undefined when x = 0, -2, and 5. Choice (C) is correct.