HSPA wrote:Is the value of a^2 - b^2 greater than the value of (3a + 3b)(2a - 2b) ?
(1) b < a
(2) a < -1
3(a+b)*2(a-b)=6(a^2-b^2);
1) b<a; a>0; b<0; let a=2 b=-3 a^2-b^2=4-9=-5 ; 6(a^2-b^2)=-30;
a>0, b>0 let a=4,b=2 a^2-b^2=16-4=12; 6(a^2-b^2)=6*12=72;
a<0, b<0 a=-1, b=-2 a^2-b^2=1-4=-3, 6(a^2-b^2)=-18;
therefore 1 alone is not sufficient to answer the question.
2) a<-1, as nothing is mentioned about b, therefore 2 alone is not sufficient to answer the question.
consider 1 and 2 together we have, b<a, and a<-1 now consider a=-2, b=-3 a^2-b^2= 4-9=-5; 6(a^2-b^2)= -30, which is less than a^2-b^2 hence
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