先化简,再求值:(2x⼀x-1 -x⼀x+1)÷x⼀x눀-1,其中x=2快啊快啊

2024-11-27 22:11:12
推荐回答(4个)
回答1:

(2x/x-1 -x/x+1)÷x/x²-1=[2x/(x-1)][(x²-1)/x -[x/(x+1)][(x²-1)/x]=2x+2-x+1=x+3=5;
x/x-2- 1-x²/x²-5x+6=2x/x-3
去分母,得x(x-3)-1-x²=2x(x-2),化简,得2x²-x-1=0,即(2x+1)(x-1)=0,解得,x=-1/2或x=1

回答2:

除号后面是不是有括号啊?如果是的话,分子分母同时乘以x²-1,变为[2x(x+1)-x(x-1)]÷x=2(x+1)-(x-1)=x+3=5

回答3:

(2x/x-1 -x/x+1)÷x/x²-1
=[2x(x+1)-x(x-1)]/(x-1)(x+1)*(x^2-1)/x
=(x^2+3x)/x
=x+3
=2+3
=5

回答4:

2-1-1+1除以 后面不变 在化简带入就可以啦