này mà lớp 1 á

Đùa nhau à

đây không phải bài lớp 1

a) \(2\left|\frac{3}{2}x-\frac{1}{4}\right|=\left|-\frac{5}{4}\right|\)

\(\Leftrightarrow\orbr{\begin{cases}2\left|\frac{3}{2}x-\frac{1}{4}\right|=\frac{5}{4}\\2\left|\frac{3}{2}x-\frac{1}{4}\right|=-\frac{5}{4}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\left|\frac{3}{2}x-\frac{1}{4}\right|=\frac{5}{4}:2\\\left|\frac{3}{2}x-\frac{1}{4}\right|=-\frac{5}{4}:2\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\left|\frac{3}{2}x-\frac{1}{4}\right|=\frac{5}{8}\\\left|\frac{3}{2}x-\frac{1}{4}\right|=-\frac{5}{8}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\frac{3}{2}x-\frac{1}{4}=\frac{5}{8}\\\frac{3}{2}x-\frac{1}{4}=-\frac{5}{8}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\frac{3}{2}x=\frac{5}{8}+\frac{1}{4}\\\frac{3}{2}x=-\frac{5}{8}+\frac{1}{4}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}\frac{3}{2}x=\frac{7}{8}\\\frac{3}{2}x=-\frac{3}{8}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{7}{8}:\frac{3}{2}\\x=-\frac{3}{8}:\frac{3}{2}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{7}{8}.\frac{2}{3}\\x=-\frac{3}{8}.\frac{2}{3}\end{cases}}\)

\(\Leftrightarrow\orbr{\begin{cases}x=\frac{7}{12}\\x=-\frac{1}{4}\end{cases}}\)

Vậy \(x\in\left\{\frac{7}{12};-\frac{1}{4}\right\}\)

\(7-\left(11+x-13\right)\div2\frac{2}{3}=2\)

\(\left(11+x-13\right)\div2\frac{2}{3}=7-2\)

\(\left(11+x-13\right)\div2\frac{2}{3}=5\)

\(11+x-13=\frac{40}{3}\)

\(11+x=\frac{79}{3}\)

\(x=\frac{46}{3}\)

Ta có:

\(7-\left(11+x-13\right)\div2\frac{2}{3}=2\)

\(7-\left(11+x-13\right)=2.2\frac{2}{3}\)

\(7-\left(11+x-13\right)=\frac{16}{3}\)

\(11+x-13=7-\frac{16}{3}\)

\(11+x-13=\frac{5}{3}\)

\(11+x=\frac{5}{3}+13\)

\(11+x=\frac{44}{3}\)

\(x=\frac{44}{3}-11\)

\(x=\frac{11}{3}\)

43/3 mình ko chắc nhé :)

Ta có:

\(\frac{6}{5}< x-\frac{3}{2}< \frac{12}{5}\)

\(=>\frac{12}{10}< x-\frac{15}{10}< \frac{24}{10}\)

\(=>\frac{12+15}{10}< x< \frac{24+15}{10}\)

\(=>\frac{27}{10}< x< \frac{39}{10}\) (mà x là số nguyên)

\(=>x=3\)

bằng 3 nha hihi

Ta có \(\frac{2}{3}-\frac{1}{3}.\left(x-\frac{3}{2}\right)-\frac{1}{2}\left(2x+1\right)=5.\)

\(\Rightarrow\frac{2}{3}-\frac{1}{3}.x+\frac{1}{3}.\frac{3}{2}-\frac{1}{2}.2x-\frac{1}{2}=5\)

\(\Rightarrow\frac{2}{3}-\frac{x}{3}+\frac{1}{2}-x-\frac{1}{2}=5\)

\(\Rightarrow\frac{4}{6}-\frac{2x}{6}+\frac{3}{6}-\frac{6x}{6}-\frac{3}{6}=\frac{30}{6}\)

\(\Rightarrow4-2x+3-6x-3=30\)

\(\Rightarrow4-8x=30\)

\(\Rightarrow-8x=26\)

\(\Rightarrow x=\frac{26}{-8}=-\frac{13}{4}\)

Vậy \(x=-\frac{13}{4}\)

\(-\frac{4}{8}=-\frac{1}{2}=\frac{5}{-10}=-\frac{7}{14}=\frac{12}{-24}\Rightarrow x=5;y=14;z=12\)

khó @gmail.com

x=5

y=14

z=12

+) 5x - 16 = 40 + x

<=> 5x - x = 16 + 40

<=> 4x = 56

<=> x = 56 : 4

<=> x= 14

+) 3x - 6 = 5x + 2

<=> 3x - 5x = 6 + 2

<=> -2x = 8

<=> x =- 4

+) x + 15 = 20 - 4x

<=> x + 4x = 20 - 15

<=> 5x = 5

<=> x= 1 

+) -12 + x = 5x -20

<=> x - 5x = 12 - 20

<=> -4x = -8

<=> x= 2

T^T , T sai chỗ nào vậy

bạn đoán xem

#)Giải :

Đặt \(A=\frac{1}{5.6}+\frac{1}{6.7}+\frac{1}{7.8}+\frac{1}{8.9}+\frac{1}{9.10}\)

\(A=\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}+\frac{1}{9}-\frac{1}{10}\)

\(A=\frac{1}{5}-\frac{1}{10}\)

\(A=\frac{1}{10}\)

cho mk hỏi chút là tại sao ta lấy 1/5 - 1/6 r + 1/6....

\(A=\frac{1}{5\cdot6}+\frac{1}{6\cdot7}+\frac{1}{7\cdot8}+\frac{1}{8\cdot9}+\frac{1}{9\cdot10}\)

\(A=\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+...+\frac{1}{9}-\frac{1}{10}\)

\(A=\frac{1}{5}-\frac{1}{10}\)

\(A=\frac{2}{10}-\frac{1}{10}=\frac{1}{10}\)

ta có: \(1-\frac{5}{6}+\frac{7}{12}-\frac{9}{20}+\frac{11}{30}-\frac{13}{42}+\frac{15}{56}-\frac{17}{72}+\frac{19}{90}\)

\(=1-\frac{5}{2.3}+\frac{7}{3.4}-\frac{9}{4.5}+\frac{11}{5.6}-\frac{13}{6.7}+\frac{15}{7.8}-\frac{17}{8.9}+\frac{19}{9.10}\)

\(=1-\frac{1}{2}-\frac{1}{3}+\frac{1}{4}-\frac{1}{4}+\frac{1}{5}-\frac{1}{5}+\frac{1}{6}-\frac{1}{6}+\frac{1}{7}-\frac{1}{7}+\frac{1}{8}-\frac{1}{8}+\frac{1}{9}-\frac{1}{9}+\frac{1}{10}\)

\(=1-\frac{1}{2}+\frac{1}{10}=\frac{3}{5}\)

quen mat cach lam rui hiiiiiii

\(1-\frac{5}{2.3}+\frac{7}{3.4}-\frac{9}{4.5}+\frac{11}{5.6}-\frac{13}{6.7}+\frac{15}{7.8}-\frac{17}{8.9}+\frac{19}{9.10}\)

tùy you giải z, t bt tek thui -_-