Archit3110 wrote:
Bunuel wrote:
Given z > 0, is x*z > 0?
(1) xz = 3x
(2) xz = -3x
x*z>0
z>0
2.
xz=-3x
z=-3
given z>0 so x would be -ve value or say -1
so xz <0
IMO B
I have hard time understanding S2.
xz = -3x
xz+3x=0
x(z+3)=0
x=0; z=-3 (this cannot be true since we are given that z>0.)
The above case was true when x = 0.
But if x were negative - say as suggested by archit - (-1), then
xz = -3x
-1 * z = -3 * -1
z = -3
z is still negative. That means x cannot be -1 or any negative value for that matter.
If x were positive - say 1.
1 * z = -3 * 1
z = -3
Is there any other value I can try?
Bunuel, could you please help me understand what is the gap in my understanding!
Thank you!