(1)化简:(x+3y) 2 +(2x+y)(x-y)(2)分解因式:x 3 -2x 2 y+xy 2 (3)先化简,再求值.(2xy 3

2025-05-10 05:32:19
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回答1:

(1)原式=x 2 +6xy+9y 2 +2x 2 -2xy+xy-y 2 =3x 2 +5xy+8y 2
(2)原式=x(x 2 -2xy+y 2 )=x(x-y) 2
(3)原式=-2y-x+5xy,
当x=1,y=-3时,原式=6-1-15=-10.