28-35

nicboy

    

Q35:

    

If xy ≠ 0 and x²y² – xy = 6, which of
the following could be y in terms of x?

    

 

    

I.                  
1/(2x)

    

II.               
– 2/x

    

III.            
3/x

    

 

    

 

    

A.  I only

    

B.  II only

    

C.  I and II

    

D.  I and III

    

E.  II and III

    

Answer:

是怎么算的呢，谢谢

            

ernestnie

xy(xy-1)=6, assume xy=3 or -3, answer is E.

马甲007

x²y² – xy-6=（xy-3)(xy+2)=0

xy-3=0得出y=3/x

xy+2=0得出y=-2/x

答案e

nicboy

谢谢各位，很清楚了

bth

X^2y^2 –xy-6=0

=>X^2y^2 -3xy +2xy-6=0

=>Xy(xy-3) +2(xy-3)=0

=>xy-3 =0 or xy+2 =0

 

Xy=3

=>y= 3/x

 Again,

Xy=-2

Y= -2/y.

Answer is II and III.