Q23:
If x ≥ 0 and x =
A. – 4y
B.
C. y
D. 4y
E. 4y2
Answer:
If x>or = 0 and x=(8xy-16y^2)^ (1/2)
Ans: 4y
Please explan it.
Thanks!
这题太简单,等式两边同时平方,得出:
x^2=8xy-16y^2
x^-8xy-16y^2=0
(x-4y)^2=0
x=4y
Thanks!
I got it now
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