Advanced MathEasyChecking a proposed solution
Advanced Math practice question
A student claims that x = 5 is a solution of x² − 25 = 0. Which statement is correct?
- A. The claim is correct, because 5² − 25 = 0.Correct
- B. The claim is wrong, because 5² = 10.
- C. The claim is wrong, because the equation has no solution.
- D. The claim is wrong, because only x = −5 works.
Answer: A. The claim is correct, because 5² − 25 = 0.
Substituting 5 gives 25 − 25 = 0.
Why the other answers are wrong
- B. The claim is wrong, because 5² = 10.
- 5² = 25, not 10.
- C. The claim is wrong, because the equation has no solution.
- The equation has two solutions, 5 and −5.
- D. The claim is wrong, because only x = −5 works.
- −5 works too, but so does 5.
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