(4).9(x+y)2-4(x-y)2 (5).(x+y)2-4(x+y-1) (6).-x2y+2xy2-y3
来源:学生作业帮助网 编辑:作业帮 时间:2024/07/14 21:35:05
![(4).9(x+y)2-4(x-y)2 (5).(x+y)2-4(x+y-1) (6).-x2y+2xy2-y3](/uploads/image/z/9315778-58-8.jpg?t=%284%29.9%28x%2By%292-4%28x-y%292+%285%29.%28x%2By%292-4%28x%2By-1%29+%286%29.-x2y%2B2xy2-y3)
xAN0EG1M*A_a E\tt8Ό7j
퇠[p:N6UɐlB2-mww+[:F7`I|6J
d$8
(4).9(x+y)2-4(x-y)2 (5).(x+y)2-4(x+y-1) (6).-x2y+2xy2-y3
(4).9(x+y)2-4(x-y)2 (5).(x+y)2-4(x+y-1) (6).-x2y+2xy2-y3
(4).9(x+y)2-4(x-y)2 (5).(x+y)2-4(x+y-1) (6).-x2y+2xy2-y3
(5x+y)(x+5y)
(x+y-2)2
-y(x-y)2
(4)5x平方+26xy+5y平方
(5)(x+y)2-4(x+y)+4=(x+y-2)2
(6)-y(x2-2xy+y2)=-y(x-y)2
(4). 9(x+y)^2-4(x-y)^2
=[3(x+y)-2(x-y)][3(x+y)+2(x-y)]
=(x+5y)(5x+y);
(5). (x+y)^2-4(x+y-1)
=(x+y)^2-4(x+y)+4
=(x+y-2)^2;
(6). -x^2y+2xy^2-y^3
=-y(x^2-2xy+y^2)
=-y(x-y)^2.
解:
4). 9(x+y)^2-4(x-y)^2
=<3(x+y)+2(x-y)><3(x+y)-2(x-y)>
=(5x+y)(x+5y)
(5). (x+y)^2-4(x+y-1)
=(x+y)^2-4(x+y)+4
=(x+y-2)^2
(6). -x^2y+2xy^2-y^3
=-y(x^2-2xy+y^2)
=-y(x-y)^2