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Re: Is the product of j, k, l and m, or jklm, an odd number? [#permalink]
10 Nov 2012, 05:01
Is the product of j, k, l and m, or jklm, an odd number?
(1) j^4 + k^4 + l^2 + m^2 = 0 --> j^4, k^4, l^2, and m^2 are all non-negative numbers. The sum of non-negative numbers is zero only when all of them equal to zero, thus j=k=l=m=0 --> jklm=0=even. Sufficient.
(2) -j = k = -l = m. If all variables equal to zero, then the answer is NO but if k=m=1 and j=l=-1, then the answer is YES. Not sufficient.