(1)原式=-4a•ab2+(-4a)•3a2b+(-4a)•(-1) =-4a2b2-12a3b+4a.
(2)原式=x6y2÷(-0.6xy)+x3y5÷(-0.6xy)+(-0.9x2y3)÷(-0.6xy) =-x5y-2x2y4+xy2.
(3)原式=a3-2a2+3a-6-a3+2a2+2a =5a-6.
(4)原式=4x2-4xy+y2-4x2-8xy+4xy+8y2 =-8xy+9y2.
(5)原式=[(a+b)-1]2 =(a+b)2-2(a+b)+1 =a2+b2+2ab-2a-2b+1.
(6)[(3x+2y)(3x-2y)-(x+2y)(5x-2y)]÷4x =[9x2-4y2-5x2+2xy-10xy+4y2]÷4x =(4x2-8xy)÷4x =x-2y. |