Solve for x: x² - 16x + 63 = 0
Difficulty: Medium
About this MCQ
Medium ACT item. Correct choice: B. x = 7 or x = 9.
- A. x = 8 or x = 8
Why not A: “x = 8 or x = 8” is not x = 7 or x = 9.
- B. x = 7 or x = 9 ✓
- C. x = 7 or x = 10
Why not C: “x = 7 or x = 10” is not x = 7 or x = 9.
- D. x = -7 or x = -9
Why not D: “x = -7 or x = -9” is not x = 7 or x = 9.
Correct answer
B. x = 7 or x = 9
Explanation
x = 7 or x = 9 (option B) is the accepted answer to “Solve for x: x² - 16x + 63 = 0”. Option A (x = 8 or x = 8) is a different value from x = 7 or x = 9. Option C (x = 7 or x = 10) is a different value from x = 7 or x = 9. Option D (x = -7 or x = -9) is a different value from x = 7 or x = 9. Keep x = 7 or x = 9 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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