计算：①x-1分之x+2*x^2-4分之x^2-1②x^2-3x+2分之x^2+3x+2*3x+3分之2x-x^2

题目

计算：①x-1分之x+2*x^2-4分之x^2-1②x^2-3x+2分之x^2+3x+2*3x+3分之2x-x^2
③2ab分之a^2-b^2*a^2-ab-2b^2分之a^2-2ab④x+y分之12xy^2除以x^2-y^2分之4xy⑤(3b^2分之2a)^2除以(-b分之a)^3⑥2ab除以2ab分之1*2b分之a⑦2x分之x+2*x^2+5x+6分之x^3-3x^2除以x^2+2x-3分之x^3-9x⑧x+y分之x^2-4y^2除以(x^2-2xy)除以x^2-y^2分之x^2+xy-2y^2
计算：
第一题：x-1分之x+2*x^2-4分之x^2-1
第二题：x^2-3x+2分之x^2+3x+2*3x+3分之2x-x^2
第三题：2ab分之a^2-b^2*a^2-ab-2b^2分之a^2-2ab
第四题：x+y分之12xy^2除以x^2-y^2分之4xy
第五题：(3b^2分之2a)^2除以(-b分之a)^3
第六题：2ab除以2ab分之1*2b分之a
第七题：2x分之x+2*x^2+5x+6分之x^3-3x^2除以x^2+2x-3分之x^3-9x
第八题：x+y分之x^2-4y^2除以(x^2-2xy)除以x^2-y^2分之x^2+xy-2y^2

答案

⑴(x+2/x-1)* (x^2-1/x^2-4)
=（（x+2)*(x+1)*(x-1)）/（（x-1）*（x-2)*x+2)
=（x+1)/(x-2)
⑵(x^2+3x+2/x^2-3x+2)*(2x-x^2/3x+3)
=((x+1)*(x+2)*(-x)*(x-2))?((x-1)*(x-2)*3*(x+1)
=(-1/3)x(x+2)/(x-1)
⑶(a^2-b^2/2ab)*(a^2-2ab/a^2-ab-2b^2)
=((a+b)*(a-b)*a*(a-2b))/(2ab*(a-2b)*(a+b))
=(a-b)/(2b)
⑷(12xy^2/x+y)*(x^2-y^2/4xy)
=(12xy^2*(x+y)*(x-y))/(4xy*(x+y))
=3y*(x-y)
⑸[(2a/3b^2)^2]*[(-b/a)^3]
=[4a^2/9b^4]*[-b^3/a^3]
=-4a^2b^3/9a^3b^4
=-(4/9)*1/(ab)
⑹(x+2/2x)*(x^3-3x^2/x^2+5x+6)*(x^2+2x-3/x^3-9x)
=（(x+2）*x^2*（x-3)*(x+3)*(x-1))/(2x*(x+2)*(x+3)*x*(x-3)*(x+3))
=(1/2)*(x-1)/2(x+3)
⑺(x^2-4y^2/x+y)*(1/x^2-2xy)*(x^2-y^2/x^2+xy-2y^2)
=((x+2y)*(x-2y)*(x+y)*(x-y))/((x+y)*(x-2y)*x*(x+2y)*(x-y))
=1/x