exponents problem

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Re: exponents problem

by Sunny22uk » Fri Sep 12, 2008 5:38 pm
gmataug08 wrote:if S^2 x T^-2 = 1 and ST = -4 , what is the value of S + T ?
S^2 x T^-2 = 1 means S^2 /T^2 = 1 i.e. s/t=+1 or -1
Since ST = -4, either s or t is -ve because square of an integer can never be negative
s*s=4
we conclude that s=+2 or -2
Consequently, t=-2 when s=2 and vice versa
IMO answer is 0
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