Is X > Y^2?
1) X > Y+5
2) X^2 - Y^2 = 0
Please explain. Thanks!
Got C, hope it's right. I spend way more than 2 mins. what' OA?
1) x > y+5
Try x=7, y=1: 7>1 yes!
Try x=1, y=-5: 1>25 No!
2) x^2 - y^2 = 0
This is same as |x| = |y|
This means that the sign doesn't matter.
In other word, (+/-)x = (+/-)y
Try x=1, x=-1 => (+/-)1 will not be greater than 1
Try x=0, 0 will not be greater than 0.
Try large number, say x=10
(+/-)10 will not ever be greater than 100
*However, if you plug in 0<x<1, then x>y^2
This means that only 0<x<1 works but not others.
Together, we know that x-y > 5. This means that the difference between them is more than 5. From |x|=|y|, it tell us that x and y will always have different sign and their value is at least 2.5
This is actually sufficient to answer the question since x won't be between 0 and 1.
*I edited this post.*