The SAT Math exam contains questions where you'll need to know how to factor down a quadratic equation. The following practice questions ask you to do that, and then to plug in your solution to solve a given expression.
Practice questions
- What is the value of
if a – b = 1/3 and a + b = 6? - What is the value of p2 + q2 if p2 – q2 = 7 and p4 – q4 = 28? A. 2 B. 3 C. 4 D. 5
Answers and explanations
- The correct answer is 25.
Remember that a2 – b2 = (a + b)(a – b). Plug in the values of a + b and a – b to solve for a2 – b2:
Now plug 2 in for a2 – b2:
- The correct answer is Choice (C).
Start by factoring p4 – q4:
Now plug in the values that the question gives you:
