neeti2711 wrote:If x≠0 and x=√ (4xy-4y^2), then in terms of y, x=
(A) 2y
(B) y
(C) y/2
(D) 4y^2/(1-2y)
(E) -2y
An alternate approach is to plug in a value for y and solve for x.
Let y=1.
Plugging y=1 into x=√(4xy-4y²), we get:
x = √(4x*1 - 4*1²)
x = √(4x - 4)
x² = 4x - 4
x² - 4x + 4 = 0
(x-2)² = 0
x=2. This is our target.
Now we plug y=1 into the answers to see which yield our target of 2.
Only
A works:
2y = 2*1 = 2.
The correct answer is
A.
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