1.约分:a²-3a+2/a²-4a+3 2.化简:(1)3+2x-x²/x²-7x+12 (2)二分之一x

问题描述:

1.约分:a²-3a+2/a²-4a+3 2.化简:(1)3+2x-x²/x²-7x+12 (2)二分之一x
3.如果x/2=y/3=z/4≠0,那么x+y+z/x+y+z的值是:
A .7 B.8 C.9 D.10

1、a²-3a+2/a²-4a+3 =(a-2)(a-1)/(a-3)(a-1)=(a-2)/(a-3)
2 、 3+2x-x²/x²-7x+12 =-(x-3)(x+1)/(x-3)(x-4)=-(x+1)/(x-4)