急、数学题

来源:百度知道 编辑:UC知道 时间:2024/06/02 12:16:20
化简下列各题
(过程)!!!
(1)(5a+4c+7b)+(5c-3b-6a)=
(2)(8xy -x2+y2)-(x2-y2+8xy)=
(3)(2x2-1/2+3x)-4(x-x2+1/2)=
(4)3x2-(7x-(4x-3)-2x2)=
请写出过程!!!!

(1)(5a+4c+7b)+(5c-3b-6a)
=(5a-6a)+(7b-3b)+(4c+5c)
=-a+4b+9c
(2)(8xy -x2+y2)-(x2-y2+8xy)
=(8xy -8xy)-(x2+x2)+(y2+y2)
=(2y2-2x2)
=2(y2-x2)
=2(y-x)(y+x)
(3)(2x2-1/2+3x)-4(x-x2+1/2)
=(2x2+4x2)+(3x-4x)-(1/2+1/2)
=6x2-x-1
(4)3x2-(7x-(4x-3)-2x2)
= 3x2-(7x-4x+3-2x2)
=3x2-7x+4x-3+2x2
=5x2-3x-3

(1)4b-a+9c
(2)2y2-2x2
(3)6x2-x-1
(4)5x2-3x-3

1:5a+4casa+7b+5c-3d1s6546=123