1,(1):3x(x-y) 关键点:x2-y2=(x+y)(x-y)
(2) :y+1 关键点:y2+2y+1=(y+1)2
2,(1) :4 x/y=3,则x=3y,带入后边的式子即可.
(2) :11 x-1/x=3,两边平方得x2+1/x2=11
3,y=(x+1)/(x-1)
4,因为1/x-1/y=3,所以x=y/(3y+1),把这个式子带入要求解的算式可得其值为 4.
1,(1):3x(x-y) 关键点:x2-y2=(x+y)(x-y)
(2) :y+1 关键点:y2+2y+1=(y+1)2
2,(1) :4 x/y=3,则x=3y,带入后边的式子即可.
(2) :11 x-1/x=3,两边平方得x2+1/x2=11
3,y=(x+1)/(x-1)
4,因为1/x-1/y=3,所以x=y/(3y+1),把这个式子带入要求解的算式可得其值为 4.