Question

计算:(x-1)/(x^2 + 3x + 2) + 6/(2 + x - x^2) - (10-x)/(4-x^2)

Answer 1

(x-1)/(x^2 + 3x + 2) + 6/(2 + x - x^2) - (10-x)/(4-x^2)=(x-1)/(x+1)(x+2)-6/(x-2)(x+1)-(10-x)/(x+2)(x-2)=[(x-1)(x-2)-6(x+2)-(10+x)(x+1)]/(x+1)(x+2)(x-2)=(x^2-3x+2-6x-12-10x-10-x^2-x)/(x+1)(x+2)(x-2)=(-...