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
y−2x
x
2
+
y
2
x1 3
−
y
2
y3 2
.
x
2
答
(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+
xy2-1 3
yx2中3x2y和-3 2
yx2,-2xy2和3 2
xy2是同类项,1 3
3x2y-2xy2+
xy2-1 3
yx23 2
=(3-
)x2y+(-2+3 2
)xy21 3
=
x2y-3 2
xy2.5 3