Question

几道七年级数学题

（1）化简：（xy-x-y+1）/（y²-2y+1）

（2）计算：（x²+3x+2/x²-3x+2）·（2x-x²/3x+3）

（3）计算：（a²-b²/2ab）·（a²-2ab/a²-ab-2b²）

（4）计算：（x+2/x）·（x³-3x²/x²+5x+6）÷（x³-9x/x²+2x-3）

（5）计算：（x²-4y²/x+y）÷（x²-2xy）÷（x²+xy-2y²/x²-y²）
（注：所有题都要有过程）

Answer 1

1、原式=[x(y-1)-(y-1)]/[(y-1)(y-1)]
=[(x-1)(y-1)]/[(y-1)(y-1)]
=（x-1）/(y-1)
2、原式=[-(x+2)(x+1)x(x-2)]/[(x-2)(x-1)3(x+1)]
=-x(x+2)/3(x-1)
3、原式=[(a+b)(a-b)a(a-2b)]/[2ab(a+b)(a-2b)]
=(a-b)/2b
4、原式=[(x+2)xx(x-3)(x+3)(x-1)]/[x(x+2)(x+3)x(x+3)(x-3)]
=(x-1)/(x+3)
5、原式=[(x-2y)(x+2y)(x+y)(x-y)]/[(x+y)x(x-2y)(x-y)(x+2y)]
=1/x

Answer 2

（1）原式=(y-1)(x-1) / (y-1)²=(x-1)/ (y-1)
（2）原式=((x+1)(x+2)/(x-1)(x-2))*(x(2-x)/3(x+1))=-(x+2)x/3(x-1)
（3）原式=((a+b)(a-b)/2ab)*(a(a-2b)/(a-2b)(a+b))=(a-b)/2b
（4）原式=((x+2)/x)*(x²(x-3)/(x+2)(x+3)÷(x(x+3)(x-3)/(x+3)(x-1))=(x-1)/(x+3)
（5）原式=((x+2y)(x-2y)/(x+y))÷(x(x-2y))÷((x+2y)(x-y)/(x-y)(x+y))=1/x

Answer 3

1）化简：（xy-x-y+1）/（y²-2y+1）化简为[（y-1）(x-1)] / (y-1)² 由此可得为（x-1）/ (y-1)

Answer 4

啥题目

Answer 5

1 原式=(y-1)(x-1) / (y-1)²=(x-1)/ (y-1)

Answer 6

nai