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Advanced MathEasyEquation with two opposite solutions

Advanced Math practice question

Which of the following equations has both 3 and −3 as solutions?

  1. A. x² = 9Correct
  2. B. x = 9
  3. C. x² = −9
  4. D. 2x = 6

Answer: A. x² = 9

3² = 9 and (−3)² = 9.

Why the other answers are wrong

B. x = 9
x = 9 has the single solution 9.
C. x² = −9
No real number squares to −9.
D. 2x = 6
2x = 6 has only x = 3.

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