If x and y are distinct integers, is (x + 7y)^3 > 0?
(1) x^2 > 49y^2
(2) x < 7y
OA: C
Source: Knewton
(1) x^2 > 49y^2
(2) x < 7y
OA: C
Source: Knewton
(x + 7y)^3 = (x + 7y)^2*(x + 7y) is greater than zero ifrahul.s wrote:If x and y are distinct integers, is (x + 7y)^3 > 0?
(1) x^2 > 49y^2
(2) x < 7y
OA: C
Source: Knewton
x+7y>0
1) (x^2-(7y)^2) >0
(x+7y) (x-7y) >0
either (x+7y), (x-7y) both greater than zero or (x+7y), (x-7y) both less than zero, Insufficient
2) x-7y<0 not sufficient to conclude anything about x+7y
Combining x-7y<0 => x+7y <0 which is sufficient to answer the question
C
