指出下列多项式中的同类项,并合并: (1)3x-2y+1+3y-2x-5; (2)3x2 y−2xy2 +1/3xy2 −3/2yx2 .

问题描述:

指出下列多项式中的同类项,并合并:
(1)3x-2y+1+3y-2x-5;
(2)3

x
y−2x
y
+
1
3
x
y
3
2
y
x

(1)3x-2y+1+3y-2x-5中3x和-2x,-2y和3y,1和-5是同类项,
3x-2y+1+3y-2x-5
=(3-2)x+(-2+3)y+(1-5)
=x+y-4.
(2)3x2y-2xy2+

1
3
xy2-
3
2
yx2中3x2y和-
3
2
yx2,-2xy2
1
3
xy2是同类项,
3x2y-2xy2+
1
3
xy2-
3
2
yx2
=(3-
3
2
)x2y+(-2+
1
3
)xy2
=
3
2
x2y-
5
3
xy2