Đáp án:
Giải thích các bước giải:
7.
a) $x \in {-6,-5,-4,-3,-2}
b) x \in {-2,-1,0.1.2}
c) x \in {-1,0,1,2,3,4,5,6}
d) x \in {-5,-4,-3,-2,-1,0,1,2,3,4,5}$
8. a) $ x \in {-3,-2,-1,0,1,2}$ suy ra tổng bằng -3
b) $x \in {-4,-3,-2,-1,0,1,2,3,4}$ suy ra tổng bằng 0
c) $x \in {-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5}$ suy ra tổng bằng -9-8-7-6=-30
d) $ x \in {-5,-4,-3,-2,-1,0,1,2,3,4$ suy ra tổng bằng -5
9. e) $x \in {-1,0,1,2,3,4}$
f) $ x \in {-5,-4,-3,-2,-1,0,1,2,3,4}$
a) -21+21=0
b) -11+23+21=12+21=33
c)=58(75+50-25)=58.100=5800
d) =(-23-17)+(13+57)=-40+70=30