It appears that the above equations can be reorganized a bit to make it easy for the further processing:
x = sqrt(4xy - 4y^2)
x^2 = 4xy - 4y^2
x^2 - 4xy + 4y^2 = 0
(x-2y)^2 = 0
x- 2y = 0
x = 2y
Answer is A
500 PS
This topic has expert replies
Source: Beat The GMAT — Problem Solving |
-
BTGmoderatorRO
- Moderator
- Posts: 772
- Joined: Wed Aug 30, 2017 6:29 pm
- Followed by:6 members
Given that x = sqrt(4xy - 4y^2)
square both side, we have
x^2 = 4xy - 4y^2
The above equation can be rewritten as
x^2 - 4xy - 4y^2= 0
Mathematically,
(x-2y)^2 = x^2 - 4xy - 4y^2
we can rewrite (x-2y)^2=0
square both side, we have x-2y = 0
i.e eliminating the square at the left hand side of the equation.
x-2y = 0
x=2y
option A is correct
square both side, we have
x^2 = 4xy - 4y^2
The above equation can be rewritten as
x^2 - 4xy - 4y^2= 0
Mathematically,
(x-2y)^2 = x^2 - 4xy - 4y^2
we can rewrite (x-2y)^2=0
square both side, we have x-2y = 0
i.e eliminating the square at the left hand side of the equation.
x-2y = 0
x=2y
option A is correct
