2/(x-1)-(a+1)/(x+2)
=(2x+4-ax-x+a+1)/(x-1)(x+2)=3a/(x-1)(x+2)
x(1-a)+a+5=3a
x=(3a-5)/(1-a)
x不等于1,a不等于3/2,
x不等于-2,a不等于3,
1-a不等于0,a不等于1,
整数a不等于1和3.
2/(x-1)-(a+1)/(x+2)
=(2x+4-ax-x+a+1)/(x-1)(x+2)=3a/(x-1)(x+2)
x(1-a)+a+5=3a
x=(3a-5)/(1-a)
x不等于1,a不等于3/2,
x不等于-2,a不等于3,
1-a不等于0,a不等于1,
整数a不等于1和3.