Question

  сократите дробь
    a-b
_______  =?
b^2-a^2


x^2-16

______   =?
16-4x

4x^2-1
_____   =?

y-2xy

Answer 1

1) (a-b)/(b^2-a^2)=(a-b)/(-a^2+b^2)=-(a-b)/(a^2-b^2)=-(a-b)/((a+b)*(a-b)=-1/(a+b)

2)(x^2-16)/(16-4x)=(x^2-16)/(-4x+16)=-(x^2-16)/(4x-16)=-(x^2-16)/((4*(x-4))=

=-((x+4)*(x-4))/(4*(x-4))=-(x+4)/4

3) (4x^2-1)/(y-2xy)=(4x^2-1)/(-y*(2x-1))=-((2x+1)*(2x-1))/(y*(2x-1))=-(2x+1)/y