Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a.x={-17;-16;-15;...;-1;0;1;2;...;18}
tổng:18
b.x={-24;-23;-22;...;-1;0;1;2;...24}
tổng:0
a) x = -19;-18;-17;....;0;1;2;3...;17;18;19;20
Vậy tổng = (-19 + 19) + (-18+18) + (-17+17)+....+(0+0) +20 = 20
b) x = -18;-17;-16;.......;0;1;2;3;....;16;17
Tương tự như câu a) Tổng = -18
c) x = 0;1;2;3;-1;-2;-3
Vậy tổng = 0
d) x = 0;1;2;3;4 ;-1;-2;-3;-4
Vậy tổng = 0
7) \(\dfrac{-5}{17}+\dfrac{3}{17}\le\dfrac{x}{17}\le\dfrac{13}{17}+\dfrac{-11}{17}\)
\(\Rightarrow\dfrac{-2}{17}\le\dfrac{x}{17}\le\dfrac{2}{17}\)
\(\Rightarrow-2\le x\le2\)
\(\Rightarrow x\in\left\{-2;-1;0;1;2\right\}\)
8) \(\dfrac{2}{3}\left(\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{1}{3}\right)\le\dfrac{x}{18}\le\dfrac{7}{3}\left(\dfrac{1}{2}-\dfrac{1}{6}\right)\)
\(\Rightarrow\dfrac{2}{3}\left(\dfrac{6}{12}+\dfrac{9}{12}-\dfrac{4}{12}\right)\le\dfrac{x}{18}\le\dfrac{7}{3}\left(\dfrac{6}{12}-\dfrac{2}{12}\right)\)
\(\Rightarrow\dfrac{2}{3}\cdot\dfrac{11}{12}\le\dfrac{x}{18}\le\dfrac{7}{3}\cdot\dfrac{4}{12}\)
\(\Rightarrow\dfrac{22}{36}\le\dfrac{x}{18}\le\dfrac{28}{36}\)
\(\Rightarrow\dfrac{11}{18}\le\dfrac{x}{18}\le\dfrac{14}{18}\)
\(\Rightarrow x\in\left\{11;12;13;14\right\}\)
8) \(\dfrac{2}{3}\left(\dfrac{1}{2}+\dfrac{3}{4}-\dfrac{1}{3}\right)\le\dfrac{x}{18}\le\dfrac{7}{3}\left(\dfrac{1}{2}-\dfrac{1}{6}\right)\\ \dfrac{2}{3}\left(\dfrac{6}{12}+\dfrac{9}{12}-\dfrac{4}{12}\right)\le\dfrac{x}{18}\le\dfrac{7}{3}\left(\dfrac{3}{6}-\dfrac{1}{6}\right)\\ \dfrac{2}{3}.\dfrac{11}{12}\le\dfrac{x}{18}\le\dfrac{7}{3}.\dfrac{2}{6}\\ \dfrac{11}{18}\le\dfrac{x}{18}\le\dfrac{14}{18}\\ \Rightarrow11\le x\le14\\ \Rightarrow x\in\left\{11;12;13;14\right\}\)
Bài 1:
$|x|\geq 25\Rightarrow x\geq 25$ hoặc $x\leq -25$
Bài 2:
$S_1=1+[(-3)+5]+[(-7)+9]+...+[(-15)+17]$
$=1+2+2+....+2$
Số lần xuất hiện của 2 là: $[(17-3):2+1]:2=4$
$\Rightarrow S_1=1+2.4=9$
-------------------------
$S_2=(-2)+[4+(-6)]+[8+(-10)]+...+[16+(-18)]$
$=(-2)+(-2)+(-2)+...+(-2)$
Số lần xuất hiện của -2 là:
$[(18-4):2+1]:2+1=5$
$\Rightarrow S_2=(-2).5=-10$
$S_1+S_2=9+(-10)=-1$
1)
B(37) = {0; 37; 74; 111;...}
2)
Ư(7) = {1; 7}
Ư(9) = {1; 3; 9}
Ư(10) = {1; 2; 5; 10}
Ư(16) = {1; 2; 4; 8; 16}
Ư(18) = {1; 2; 3; 5; 9; 18}
Ư(20) = {1; 2; 4; 5; 10; 20}
3)1) x = {0; 26; 39;52}
2) x = {0; 17; 34; 51}
3) x = {0; 12; 24; 36; 48;...}
4) x = {1; 2; 3; 5; 6; 10; 15; 30}
5) x = {0; 7; 14; 21; 28; 35; 42;49}
Sai thì thôi nha
HỌC TỐT!!!
\(\Leftrightarrow\frac{-2}{17}\le\frac{x}{17}\le\frac{2}{17}\Rightarrow x\in\left(-2;-1;0;1;2\right)\)
\(\Leftrightarrow\frac{-1}{24}\le\frac{x}{24}\le\frac{5}{24}\Rightarrow x\in\left(-1;0;1;2;3;4;5\right)\)
2 câu sau tự làm nha
\(-\frac{5}{17}+\frac{3}{17}\le\frac{x}{17}\le\frac{13}{17}+-\frac{11}{17}\)
\(\frac{-2}{17}\le\frac{x}{17}\le\frac{2}{17}\)
=> \(x\in\left\{-2;-1;0;1;2\right\}\)
tìm n 
giúp mik với sắp thi r
\(a)\frac{1}{3}+\frac{-2}{5}+\frac{1}{6}+\frac{-1}{5}\le x< \frac{-3}{4}+\frac{2}{7}+\frac{-1}{4}+\frac{3}{5}+\frac{5}{7}\)
\(\Rightarrow\frac{1}{3}+\frac{1}{6}+\frac{-2}{5}+\frac{-1}{5}\le x< \frac{-3}{4}+\frac{-1}{4}+\frac{2}{7}+\frac{5}{7}+\frac{3}{5}\)
\(\Rightarrow\frac{2}{6}+\frac{1}{6}+\frac{-3}{5}\le x< -1+1+\frac{3}{5}\)
\(\Rightarrow\frac{1}{2}+\frac{-3}{5}\le x< \frac{3}{5}\)
\(\Rightarrow\frac{-1}{10}\le x< \frac{6}{10}\)
\(\Rightarrow-1\le x< 6\)
\(\Rightarrow x\in\left\{-1;0;1;2;3;4;5\right\}\)
Bài b tương tự
1)-20<x<21
=>x\(\varepsilon\){-19;-18;-17;-16;-15;-14;-13;-12;...;12;13;14;15;16;17;18;19;20}
2)-18<x<17
=>x\(\varepsilon\){-18;-17;-16;-15;...;15;16;17}
3)-27<x<27
=>x\(\varepsilon\)
1.a) tổng=18
b)tổng=0
3.
S1=-18
S2=18
S1+S2=0
a, x=-17,-16,-15,-14,-13,-12,-11,-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18.
b, x=