sana.noor wrote:if a² ≥ 25, which of the following must be true?
1) a ≥ 5
2) a ≤ -5
3) a ≥ 10 OR a ≤ -10
4) a ≥ 5 OR a ≤ -5
5) -5 ≤ a ≤ 5
4
Show that four of the five answer choices DON'T have to be true.
Be sure to satisfy the constraint that a² ≥ 25.
It's possible that a = 6, since 6² ≥ 25.
Eliminate B, since it does not have to be true that a ≤ - 5.
Eliminate C, since it does not have to be true that a ≥ 10 or a ≤ -10.
Eliminate E, since it does not have to be true that -5 ≤ a ≤ 5.
It's possible that a = -6, since (-6²) ≥ 25.
Eliminate A, since it does not have be true that a ≥ 5.
The correct answer is
D.
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