LUANDATO wrote:Does a = 0?
(1) a^3(8.12) = a^4(8.12)
(2) ab ≠b
The OA is C.
I need help to solve this DS question. Can any expert explain it, please? Thanks.
(1) a^3(8.12) = a^4(8.12)
Case 1: Say a = 0, then a^3(8.12) = a^4(8.12). The answer is Yes.
Case 2: Say a = 1, then a^3(8.12) = a^4(8.12). The answer is No. No unique answer. Insufficient.
(2) ab ≠b
Case 1: Say a = 0 and b = any number other than 0. The answer is Yes.
Case 2: Say a and b = any number other than 0 and ±1. The answer is No. No unique answer. Insufficient.
(1) and (2) combined:
Since from (1), a = 0 or 1, and from (2), a ≠1, thus, a = 0. Sufficient.
The correct answer:
C
Hope this helps!
-Jay
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