Is nm^2 + nm - 12n = 0? (1) m^2 = 16 (2) m = -4

Question

Is  nm^2 + nm - 12n = 0?

(1) m^2 = 16
(2) m = -4

bb · Answer

Moving this topic to the data sufficiency sub forum.

Posted from my mobile device

Kinshook · Answer

@1992SonalAsked: Is  nm^2 + nm - 12n = 0?
Is  n(m^2 + m - 12) = 0?
Is n(m+4)(m-3) = 0?

(1)   m^2 = 16
If m = 4; n(m+4)(m-3) is NOT necessarily 0
If m=-4; n(m+4)(m-3) = 0
NOT SUFFICIENT

(2)   m = -4 
n(m+4)(m-3) = 0
SUFFICIENT

IMO B

illegallyblonde · Answer

Kinshook  I don't understand how (2) is sufficient?

If m = 4 then it makes sense because n(m-4)(m+3) = n(4-4)(4+3) = 0
but doesn't m = -4 mean n(-4-4)(-4+3) = n(-8)(-1) = 8n?

Kinshook · Answer

helpmegmat

Please see the revised solution

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