问题标题:
八下数学题分式1.先化简再求值(1-x)²(1+x)²/(x²-1)²,其中x=-1/22.已知x/3=y/4=8/6不等于0,求x+y-z/x-y+z的值
问题描述:
八下数学题分式
1.先化简再求值(1-x)²(1+x)²/(x²-1)²,其中x=-1/2
2.已知x/3=y/4=8/6不等于0,求x+y-z/x-y+z的值
苏炜回答:
1.【(1-x)*2(1+x)】/【(x+1)(x-1)】=(1-x)*2/(x-1)=x-1=-1/2-1=-3/2
2.x=3/4yy=yz=6/4y
代入(x+y-z)/(x-y+z)=(3/4y+y-6/4y)/(3/4y-y+6/4y)=1/2
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