把下列各式约分;①a方-b方分之-a+b ② 9ab方(1-m)分之-3a方b(m-1)③12xy方(y-x)分之2x方
3个回答

①a方-b方分之-a+b =(-a+b)/(a-b)(a+b)=-1/(a+b)

② 9ab方(1-m)分之-3a方b(m-1)=[-3a²b(m-1)]/[9ab²(1-m)]=a/b

③12xy方(y-x)分之2x方y(x-y)方=[2x²y(x-y)]/[12xy²(y-x)]=-x/6y

④4x方-1分之6x方-3x=3x(2x-1)/(2x-1)(2x+1)=3x/(2x+1)

⑤x方-2x+1分之x方-1=(x²-1)/(x²-2x+1)=(x-1)(x+1)/(x-1)²=(x+1)/(x-1)

⑥2x-y分之y方-4xy+4x方=(2x-y)²/(2x-y)=2x-y

⑦3x方-75分之x方-10x+25=(x²-10x+25)/3(x²-25)=(x-5)²/3(x-5)(x+5)=(x-5)/3(x+5)

⑧3x方-75分之x方-10x+25=(x²-10x+25)/3(x²-25)=(x-5)²/3(x-5)(x+5)=(x-5)/3(x+5)