题目内容
化简:
(1)5x-y-2(x-y+1)
(2)(-
x2+4xy-
y2)-(-x2+3xy-
y2)
(1)5x-y-2(x-y+1)
(2)(-
1 |
2 |
3 |
2 |
1 |
2 |
分析:先按照去括号法则去掉整式中的小括号,再合并整式中的同类项即可.
解答:解:(1)原式=5x-y-2x+2y-2
=3x+y-2;
(2)原式=-
x2+4xy-
y2+x2-3xy+
y2
=
x2+xy-y2.
=3x+y-2;
(2)原式=-
1 |
2 |
3 |
2 |
1 |
2 |
=
1 |
2 |
点评:本题考查了整式的加减,解决此类题目的关键是熟记去括号法则,熟练运用合并同类项的法则,这是各地中考的常考点.
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