计算或化简:(1)(2)5-3×{-2+4×[-3×(-2)2-(-4)÷(-1)3]-7}(3)(3a2-2)+(a2-3a)-(-2a2+5a+5)(4)5a2-

发布时间:2020-08-07 19:50:55

计算或化简:
(1)
(2)5-3×{-2+4×[-3×(-2)2-(-4)÷(-1)3]-7}
(3)(3a2-2)+(a2-3a)-(-2a2+5a+5)
(4)5a2-〔a2+(5a2-2a)-2(a2-3a)〕.

网友回答

解:(1)原式=(-+)×36
=-×36-×36+×36
=-27-20+21
=-26;
(2)原式=5-3×{-2+4×[-3×4-4]-7}
=5-3×{-2+4×[-12-4]-7}
=5-3×{-2+4×(-16)-7}
=5-3×{-2-64-7}
=5-3×(-73)
=5+219
=224;
(3)原式=3a2-2+a2-3a+2a2-5a-5
=6a2-8a-7;
(4)原式=5a2-(a2+5a2-2a-2a2+6a)
=5a2-a2-5a2+2a+2a2-6a
=a2-4a.
解析分析:(1)把除法变为乘法,运用乘法的分配律简便计算;
(2)按照有理数混合运算的顺序计算:先乘方,后乘除,最后算加减,有括号的先算括号里面的;
(3)和(4)都是先去括号,再合并同类项.

点评:在整式的加减运算中,如果题中有多重括号,应按照先去小括号,再去中括号,最后去大括号的顺序进行.
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