题目内容
计算或化简
(1)23-17-(-7)+(-16)
(2)-14-(1-0.5)×
×[2-(-3)2]
(3)a2-2a-4a2+a
(4)(3a2b-ab2)-4(-ab2+3a2b)
(1)23-17-(-7)+(-16)
(2)-14-(1-0.5)×
1 | 3 |
(3)a2-2a-4a2+a
(4)(3a2b-ab2)-4(-ab2+3a2b)
分析:(1)先去括号,再从左到右依次计算即可;
(2)先算括号里面的,再算乘方,乘法,最后算加减;
(3)直接合并同类项即可;
(4)先去括号,再合并同类项即可.
(2)先算括号里面的,再算乘方,乘法,最后算加减;
(3)直接合并同类项即可;
(4)先去括号,再合并同类项即可.
解答:解:(1)原式=23-17+7-16
=-3;
(2)原式=-1-0.5×
×(2-9)
=-1-
×(-7)
=-1+
=
;
(3)原式=(1-4)a2-(2-1)a
=-3a2-a;
(4)原式=3a2b-ab2+4ab2-12a2b
=(3-12)a2b-(1-4)ab2
=-9a2b+3ab2.
=-3;
(2)原式=-1-0.5×
1 |
3 |
=-1-
1 |
6 |
=-1+
7 |
6 |
=
1 |
6 |
(3)原式=(1-4)a2-(2-1)a
=-3a2-a;
(4)原式=3a2b-ab2+4ab2-12a2b
=(3-12)a2b-(1-4)ab2
=-9a2b+3ab2.
点评:本题考查的是整式的加减,熟知整式的加减实质上就是合并同类项是解答此题的关键.
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