Question

求八年级下数学书练习题(人教版)!

Answer 1

1.(2x分之3) + 2 = 0

2.(x-1分之x) + (x+1分之2) =1

3.(x+1分之1) - (x?+3x+2分之x?)=-1

答案

1.3/2x=-2

3=-4x

x=-3/4

2.x/(x-1)+2/(x+1)=1

x(x+1)+2(x-1)=(x-1)(x+1)

x^2+x+2x-2=x^2-1

3x=1

x=1/3

3.1/(x+1)-x^2/(x^2+3x+2)=-1

1/(x+1)-x^2/(x+1)(x+2)=-1

(x+2)/(x+1)(x+2)-x^2(x+1)(x+2)=-1

x+2-x^2=-(x+1)(x+2)

x^2-x-2=x^2+3x+2

4x=-4

x=-1