Question

解两个题 1.（x+2\ x^2-2x - x-1\x^2-4x+4)除以x-4\x 2.x^2-2x\x^2-1 除以

Answer 1

1.[（x+2)/(x^2-2x) - (x-1)/(x^2-4x+4)]/[(x-4)/x ]

=.[（x+2)/x(x-2)- (x-1)/(x-2)^2]*x /(x-4)

=[（x+2)(x-2)/x(x-2)^2- x(x-1)/x(x-2)^2]*x /(x-4)

=[(x^-4-x^+x)/x(x-2)^2]*x /(x-4)

=(x-4)/x(x-2)^2*x /(x-4)

=1/(x-2)^2

2.[(x^2-2x)/(x^2-1)] /[x-1 - (2x-1)/(x+1)]

=[(x^2-2x)/(x-1)(x+1)]/[(x^2-1- 2x+1)/(x+1)]

=[(x^2-2x)/(x-1)(x+1)]/[(x^2- 2x)/(x+1)]

==[(x^2-2x)/(x-1)(x+1)]*[(x+1)/(x^2- 2x)]

=1/(x-1)