Question

分式的加减

Answer 1

解
3/(x-2)(x+1)-1/(x-2)
=3/(x-2)(x+1)-(x+1)/(x-2)(x+1)
=(3-x-1)/(x-2)(x+1)
=(2-x)/(x-2)(x+1)
=-1/(x+1)

x/(x+1)-(x²+1)/(x²+x)
=x/(x+1)-(x²+1)/x(x+1)
=x²/x(x+1)-(x²+1)/x(x+1)
=(x²-x²-1)/x(x+1)
=-1/x(x+1)

2/(a²-1)+1/(a+1)
=2/(a-1)(a+1)+(a-1)/(a+1)(a-1)
=(2+a-1)/(a-1)(a+1)
=(a+1)/(a-1)(a+1)
=1/(a-1)

Answer 2

1、3/(x-2)(x+1) -(x+1)/(x-2)(x+1)
=[3-(x+1)]/(x-2)(x+1)
=(2-x)/(x-2)(x+1)
=-1/(x+1)

2、=x²/x(x+1)-(x²+1)/x(x+1)
=[x²-(x²+1)]/x(x+1)
=-1/(x²+x)

3、=2/(a+1)(a-1)+(a-1)/(a+1)(a-1)
=[2+(a-1)]/(a+1)(a-1)
=(a+1)/(a+1)(a-1)
=1/(a-1)