[問題]Gwd3-35

[migo0724]

#35
If xy≠0 and x^2y^2-xy=6 ,which of the following could be y in terms of x?
1.1/2x
2.-2/x
3.3/x

(A) 1 only
(B) 2 only
(C) 1 and 2
(D) 1 and 3
(E) 2 and 3

答案是E...為什麼是E，麻煩大家...

[huacy]

x[sup]2[/sup]y[sup]2[/sup]-xy=6
x[sup]2[/sup]y[sup]2[/sup]-xy-6=0
(xy-3)(xy+2)=0
xy=3 or xy=-2

所以 y=3/x or y=-2/x

[migo0724]

謝謝~原來不用把XY看的太嚴重就可以了~呵呵~算多了果然會卡住...多謝