1.(a-b)(x+y)-(b-a)(y-x)
2个回答

1.(a-b)(x+y)-(b-a)(y-x)

=.(a-b)(x+y)+(a-b)(y-x)

=(a-b)(x+y+y-x)

=2y(a-b)

2.(m²-6)²-6(m²-6)+9

=.(m²-6-3)²

=.(m²-9)²

=.(m+3)²×.(m-3)²

(2-4x)/(3+x)=1/2+3/(x+3)

(2-4x)/(x+3)=1/2+3/(x+3)

4-8x=x+3+6

-9x=5

x=-5/9

把x=-5/9代入最简公分母x+3≠0

所以方程的解为:x=-5/9