(1)4a2bc-8ab+32b2=4b(a2c-2a+8b);
(2)x(a-b)(b-c)-y(b-a)(b-c),
=x(a-b)(b-c)+y(a-b)(b-c),
=(a-b)(b-c)(x+y);
(3)x4-81,
=(x2+9)(x2-9),
=(x2+9)(x+3)(x-3);
(4)
-ab+b2=(a2 4
-b)2;a 2
(5)2x3-18xy2,
=2x(x2-9y2),
=2x(x+3y)(x-3y);
(6)-y3-
y+y2,1 4
=-y(y2-y+
),1 4
=-y(y-
)2.1 2