Is it C ?f2001290 wrote:is |x| = y-z
(1) x+y = z
(2) x<0
1 - insufficient. y-z = -x. Now, if x is positive, y-z = -ve and so y-z != |x|.
If x is negative, y-z = +ve and so y-z = |x|
2 - insufficient. Just knowing x<0 does not help.
1 and 2 together sufficient since y-z = -x and x is negative.












