1) We can rewrite this absolute value as two different equations: either 3x - 7 = 2x + 2, or 3x - 7 = -2x - 2.
3x = 2x + 9
x = 9
5x = 5
x = 1
x could equal 9 or 1, so the square root of x could be 3 or 1. 3 is prime, 1 is not; insufficient.
2) Easy to assume that 9 is the only value that works here, but always watch out for 0 on exponent problems! In this case, 0 satisfies statement 2) just as well. So, x could be 9 or 0, and sqrt x could b 3 or 0--prime or non-prime. Insufficient.
Combined: 9 is the only value that satisfies both equations, so the answer is (C), both statements together are sufficient to answer the question.
Is sqrt(x) a prime number?
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KapTeacherEli
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vineetbatra
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I fell for it too.
A is straight 1 or 9, but in B I divided both sides by X. Rule to remember. We cannot divide by a variable unless we are sure its not a zero.
A is straight 1 or 9, but in B I divided both sides by X. Rule to remember. We cannot divide by a variable unless we are sure its not a zero.
