Bài 3: Thứ tự trong tập hợp các số nguyên

Bài 3:

a: -50<x<50

=>\(x\in\left\{-49;-48;...;48;49\right\}\)

Tổng là 0

b: -100<x<=100

=>\(x\in\left\{-99;-98;...;98;99;100\right\}\)

Tổng là 100

c: -42<x<40

=>\(x\in\left\{-41;-40;-39;...;38;39\right\}\)

Tổng là -41-40-39-...+38+39

=-81

biểu diễn cái gì cậu? Trục số, số tp hay ps

-----|-----|-----|-----|-----|-----|-----|-----|-----|----->

     -4    -3          -1            1            3     4

\(a.\dfrac{3}{7}:x=\dfrac{-9}{28}.\\ \Leftrightarrow x=\dfrac{3}{7}:\dfrac{-9}{28}=\dfrac{-4}{3}.\\ d.x-\dfrac{1}{2}=\dfrac{1}{3}+\dfrac{3}{4}.\\ \Leftrightarrow x-\dfrac{1}{2}=\dfrac{13}{12}.\\ \Leftrightarrow x=\dfrac{19}{12}.\\ f.\dfrac{5}{4}-x=\dfrac{1}{2}-\dfrac{7}{8}.\\ \dfrac{5}{4}-x=\dfrac{-3}{8}.\\ \Leftrightarrow x=\dfrac{13}{8}.\)

\(i.3\dfrac{2}{3}x+5\dfrac{1}{2}=11\dfrac{1}{6}.\\ \Leftrightarrow\dfrac{11}{3}x+\dfrac{11}{2}=\dfrac{67}{6}.\\ \Leftrightarrow\dfrac{11}{3}x=\dfrac{17}{3}.\\ \Leftrightarrow x=\dfrac{17}{11}.\)

\(a,\dfrac{3}{7}:x=\dfrac{-9}{28}\\ \Rightarrow x=-\dfrac{4}{3}\\ d,x-\dfrac{1}{2}=\dfrac{1}{3}+\dfrac{3}{4}\\ \Rightarrow x-\dfrac{1}{2}=\dfrac{13}{12}\\ \Rightarrow x=\dfrac{19}{12}\\ f,\dfrac{5}{4}-x=\dfrac{1}{2}-\dfrac{7}{8}\\ \Rightarrow\dfrac{5}{4}-x=-\dfrac{3}{8}\\ \Rightarrow x=\dfrac{13}{8}\\ i,3\dfrac{2}{3}x+5\dfrac{1}{2}=11\dfrac{1}{6}\\ \Leftrightarrow\dfrac{11}{3}x+\dfrac{11}{2}=\dfrac{67}{6}\\ \Rightarrow\dfrac{11}{3}x=\dfrac{17}{3}\\ \Rightarrow x=\dfrac{17}{11}\)

a: 3/7:x=-9/28

\(\Leftrightarrow x=\dfrac{3}{7}:\dfrac{-9}{28}=\dfrac{3}{7}\cdot\dfrac{-28}{9}=\dfrac{-4}{3}\)

d: x-1/2=1/3+3/4

=>x-1/2=4/12+9/12=13/12

=>x=13/12+1/2=13/12+6/12=19/12

f: 5/4-x=1/2-7/8

=>5/4-x=4/8-7/8=-3/8

=>x=5/4+3/8=10/8+3/8=13/8

\(x=-4;-3;-2;-1;0;1;2;3\)

-4 , -3 , -2 , -1 , 0 ,1 , 2 , 3

A={-4;-3;-2;-1;0;1;2;3}

Đây nhá.Nếu sai thì mik cx chịu chứ cx chẳng chắc nữa

\(23:5=4\left(dư3\right)\)

\(vậy\) : \(\dfrac{23}{5}=4+\dfrac{3}{5}=4\dfrac{3}{5}\)

\(3\dfrac{4}{5}=\dfrac{3.5+4}{5}=\dfrac{19}{5}\)

b: =>12-x=-7

hay x=19

`-(-3);-1;-97;-101`

-(-3):-1:-97:-101