文档介绍:( 7) 2
b+5ab+a
2 1 3
2
+ x
+ x
( 26) 2
合并同类项
(1)4x+2y—5x—y (2)—3ab+7—2a2—9ab—3 (3)x+[x+(-2x-4y)]; (4) (a( 7) 2
b+5ab+a
2 1 3
2
+ x
+ x
( 26) 2
合并同类项
(1)4x+2y—5x—y (2)—3ab+7—2a2—9ab—3 (3)x+[x+(-2x-4y)]; (4) (a+4b)- (3a-6b)
(5)3x
2
-1-2x-5+3x-x2
(6)-
b-6ab-+5ab+a2
b
2 1 3
a - ab + a 2 +ab -b 3 2 4
2
(8)6x
2y+2xy-3x2
y
2-7x-5yx-4y2
x2
-6x
2
y
(9)8x+2y+2(5x-2y) (10)3a-(4b-2a+1)
(11)7m+3(m+2n) (12)(x
2
-y
2)-4(2x
2
-3y
2)
(13)3x
2-1-2x-5+3x-x2
(14)4xy-3y
2-3x2
+xy-3xy-2x2-4y
2
(15)-
2b-6ab-
b (15) a 2 - ab + a 2 +ab -b
3 2 4
2
(16)5(a-b)
2-7(a-b)+3(a-b)2
-9(a-b)
(17)3x
n+1-4xn-1
1 3
n+1
2 2
n-1
+5x
n-2xn
(18)3x2-1-2x-5+3x-x2
(19)-
2b-6ab-
b+5ab+a2b
(20)
2 1 3 a 2 - ab + a
3 2 4
2
+ab -b
2
(21)6x2y+2xy-3x2y2-7x-5yx-4y2x2-6x2y
(22)4x2y-8xy2+7-4x2y+12xy2-4; (23)a2-2ab+b2+2a2+2ab - b2.
(24)3x
2-1-2x-5+3x-x2
(25)-
2b-6ab-
b+5ab+a2b
2 1 3
a - ab + a 2 +ab -b 3 2 4
2
(27)6x
2y+2xy-3x
2y
2-7x-5yx-4y2x
2-6x
2y
(28)4x
2y-8xy
2+7-4x
2y+12xy
2-4;
(29)a2-2ab+b2+2a2+2ab - b2.
2
1
3、先去括号,再合并同类项:
(1)(2x-3y)+(5x+4y); (2)(8a-7b)-(4a-5b); (3)a-(2a+b)+2(a-2b); (4)3(5x