问题
解答题
用心算一算. (1)
(2)-14-[2-(-3)2]÷(-
(3)化简求值.求:3a-3b+3[2a-(b-2a)]的值,其中a=-1,b=-2. |
答案
(1)原式=
+2 3
-(1 3
+1 8
)3 8
=1-1 2
=
;1 2
(2)原式=-1-(2-9)×(-2)
=-1-14
=-15;
(3)原式=3a-3b+6a-3b+6a
=15a-3b,
当a=-1,b=-2时,原式=-15+6=-9.