Question

1）（A-B)(X-Y)-(B-A)(X+Y),2）12XY的二次方-18X的二次方Y-2Y的三次方,

Answer 1

1）（A-B)(X-Y)-(B-A)(X+Y),

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

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

=2x(a-b)

2）12XY的二次方-18X的二次方Y-2Y的三次方,

=-2y(9x²-6xy+y²)

=-2y(3x-y)²