⒈化简求值(x-1/x²-1+1/x+1)÷4/x²-x,其中,x=2。⒉解方程⑴x/x-2-1/ 20
⒈化简求值(x-1/x²-1+1/x+1)÷4/x²-x,其中,x=2。⒉解方程⑴x/x-2-1/x²-4=1⑵12/x²-9-2...
⒈化简求值(x-1/x²-1+1/x+1)÷4/x²-x,其中,x=2。⒉解方程⑴x/x-2-1/x²-4=1⑵12/x²-9-2/x-3=|/x+3
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小同学,请多用几个括号
1. [(x-1)/(x²-1)+1/(x+1)]÷4/(x²-x)=[1/(x+1)+1/(x+1)]*x(x-1)/4=2/(x+1)*x(x-1)/4
=x(x-1)/[2(x+1)]=2(2-1)/[2(2+1)]=1/3
2. 1) x/(x-2)-1/(x²-4)=1 x(x+2)/(x^2-4)-1/(x^2-4)=1
x^2+2x-1=x^2-4 x= -3/2
2) 12/(x²-9)-2/(x-3)=1/(x+3) [12-2(x+3)]/(x^2-9)=(x-3)/(x^2-9) x≠ ±3
12-2(x+3)=x-3 3x=9 x=3 与 x≠ ±3矛盾
所以,方程无解
1. [(x-1)/(x²-1)+1/(x+1)]÷4/(x²-x)=[1/(x+1)+1/(x+1)]*x(x-1)/4=2/(x+1)*x(x-1)/4
=x(x-1)/[2(x+1)]=2(2-1)/[2(2+1)]=1/3
2. 1) x/(x-2)-1/(x²-4)=1 x(x+2)/(x^2-4)-1/(x^2-4)=1
x^2+2x-1=x^2-4 x= -3/2
2) 12/(x²-9)-2/(x-3)=1/(x+3) [12-2(x+3)]/(x^2-9)=(x-3)/(x^2-9) x≠ ±3
12-2(x+3)=x-3 3x=9 x=3 与 x≠ ±3矛盾
所以,方程无解
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