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
2个回答

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