(1)原式=-8x3y6+2x3y6=-6x3y6.
(2)原式=1+4-5÷1=5-5=0.
(3)原式=20092-(2009+1)(2009-1)=20092-20092+1=1.
(4)原式=(x2-y2-x2+2xy-y2+2xy-2y2)÷(4y)=-y-x.
(1)原式=-8x3y6+2x3y6=-6x3y6.
(2)原式=1+4-5÷1=5-5=0.
(3)原式=20092-(2009+1)(2009-1)=20092-20092+1=1.
(4)原式=(x2-y2-x2+2xy-y2+2xy-2y2)÷(4y)=-y-x.