问题
解答题
(1)12-(-18)+(-7)-15; (2)-72+2×(-3)2+(-6)÷(-3)2; (3)14-
(4)2x2-{-3x+[4x2-(3x2-x)]}. |
答案
(1)12-(-18)+(-7)-15=12+18-7-15=8;
(2)-72+2×(-3)2+(-6)÷(-3)2=-49+18+(-
)=-312 3
;2 3
(3)14-
×[2-(-3)2]=1-1 6
×(-7)=21 6
;1 6
(4)2x2-{-3x+[4x2-(3x2-x)]}
=2x2+3x-4x2+3x2-x
=x2+2x.