题目内容
计算或化简:
(1)(
-
+
)×(-36)
(2)-32×(-2)+42÷(-2)3
(3)-22-(1-
×0.2)÷(-2)3
(4)(2x-y)-2(4x+
y)+2012
(5)-3(2x-y)-2(4x+
y)+2012
(6)3x2y-2[
x2y-(x2y-
x2)-2x2].
(1)(
1 |
4 |
1 |
6 |
1 |
9 |
(2)-32×(-2)+42÷(-2)3
(3)-22-(1-
1 |
5 |
(4)(2x-y)-2(4x+
1 |
2 |
(5)-3(2x-y)-2(4x+
1 |
2 |
(6)3x2y-2[
1 |
2 |
1 |
4 |
分析:(1)运用分配律计算即可;
(2)按照有理数混合运算顺序:先算乘方,再算乘除,最后算加减;
(3)按照有理数混合运算顺序:先算乘方,再算乘除,最后算加减;有括号,要先做括号内的运算;
(4)先去小括号,再合并同类项即可;
(5)先去小括号,再合并同类项即可;
(6)先去小括号,再去中括号,然后合并同类项即可.
(2)按照有理数混合运算顺序:先算乘方,再算乘除,最后算加减;
(3)按照有理数混合运算顺序:先算乘方,再算乘除,最后算加减;有括号,要先做括号内的运算;
(4)先去小括号,再合并同类项即可;
(5)先去小括号,再合并同类项即可;
(6)先去小括号,再去中括号,然后合并同类项即可.
解答:解:(1)(
-
+
)×(-36)=-9+6-4=-7;
(2)-32×(-2)+42÷(-2)3=-9×(-2)+16÷(-8)=18-2=16;
(3)-22-(1-
×0.2)÷(-2)3=-4-(1-
)÷(-8)=-4+
=-3
;
(4)(2x-y)-2(4x+
y)+2012=2x-y-8x-y+2012=-6x-2y+2012;
(5)-3(2x-y)-2(4x+
y)+2012=-6x+3y-8x-y+2012=-14x+2y+2012;
(6)3x2y-2[
x2y-(x2y-
x2)-2x2]=3x2y-2[
x2y-x2y+
x2-2x2]=3x2y-x2y+2x2y-
x2+4x2=4x2y+
x2.
1 |
4 |
1 |
6 |
1 |
9 |
(2)-32×(-2)+42÷(-2)3=-9×(-2)+16÷(-8)=18-2=16;
(3)-22-(1-
1 |
5 |
1 |
25 |
3 |
25 |
22 |
25 |
(4)(2x-y)-2(4x+
1 |
2 |
(5)-3(2x-y)-2(4x+
1 |
2 |
(6)3x2y-2[
1 |
2 |
1 |
4 |
1 |
2 |
1 |
4 |
1 |
2 |
7 |
2 |
点评:本题考查了有理数混合运算及整式的加减,是基础知识,需熟练掌握.
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