Solve for x: x² - 7x - 8 = 0
Difficulty: Medium
About this MCQ
Medium ACT item. Correct choice: D. x = -1 or x = 8.
- A. x = -1 or x = 9
Why not A: “x = -1 or x = 9” is not x = -1 or x = 8.
- B. x = 1 or x = -8
Why not B: “x = 1 or x = -8” is not x = -1 or x = 8.
- C. x = 0 or x = 7
Why not C: “x = 0 or x = 7” is not x = -1 or x = 8.
- D. x = -1 or x = 8 ✓
Correct answer
D. x = -1 or x = 8
Explanation
x = -1 or x = 8 (option D) is the accepted answer to “Solve for x: x² - 7x - 8 = 0”. Option A (x = -1 or x = 9) is a different value from x = -1 or x = 8. Option B (x = 1 or x = -8) is a different value from x = -1 or x = 8. Option C (x = 0 or x = 7) is a different value from x = -1 or x = 8. Keep x = -1 or x = 8 as the ACT fact for this stem.
Source: Original practice question, MCQsHub
Tags: Math, Algebra, American Exams, ACT
Submitted by: MCQsHub Editorial
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