1.原式=-6(x-y) 3+3y(x-y) 3=3(x-y) 3*(y-2)
2.原式=(x-y)(x+y)-2y-5=x+y-2y-5=x+y-5=1-5=-4
3.原式=56 2+2*56*44+44 2=(56+44)2=100*100=10000
4.原式=(x-y)(x 2+3xy+y 2-5xy)=(x-y)(x 2-2xy+y 2)=(x-y) 3=
(6.61+3.39) 3=10*10*10=1000
5.原式=( 10(a-b)±20(a+b) ) 2
2k+4=±20*10*2
k=198或-202