\(x\times\frac{6}{25}=\frac{15}{-13}\)

x=\(\frac{15}{-13}\div\frac{6}{25}\)

x=\(-\frac{125}{26}\)

các câu còn lại làm tương tự nha!!!

\(1.x.\frac{6}{25}=\frac{15}{-13}\\ x=\frac{15}{-13}:\frac{6}{25}\\ x=-\frac{125}{26}\)

\(2.x:\frac{4}{10}=\frac{13}{-45}+\frac{8}{15}\\ x:\frac{4}{10}=\frac{11}{45}\\ x=\frac{11}{45}.\frac{4}{10}\\ x=\frac{22}{225}\)

\(3.\frac{3}{8}-\frac{1}{6}.x=\frac{1}{4}\\ \frac{1}{6}.x=\frac{3}{8}-\frac{1}{4}\\ \frac{1}{6}.x=\frac{1}{8}\\ x=\frac{1}{8}:\frac{1}{6}\\ x=\frac{3}{4}\)

\(4.\frac{1}{3}+\frac{1}{2}:x=-4\\ \frac{1}{2}:x=-4-\frac{1}{3}=-\frac{13}{3}\\ x=\frac{1}{2}:\left(-\frac{13}{3}\right)=-\frac{3}{26}\)

\(5.x+\frac{7}{12}=\frac{17}{18}-\frac{1}{9}=\frac{5}{6}\\ x=\frac{5}{6}-\frac{7}{12}\\ x=\frac{1}{4}\)

mk sắp phải đi học rồi các bạn giúp mình với có đc ko mk nhớ sẽ đền đáp công ơn của bạn 

a) (5 - x) +12 = -25

<-> 5 - x + 12 = -25

<-> 17 - x = - 25

<-> x = 42

b) 12 - 4(x - 2) = -4

<-> 12 - 4x + 8 = -4

<-> 20 - 4x = -4

<-> 4x = 24

<-> x = 6

\(\left|x+\frac{1}{2}\right|-15\frac{1}{2}=-12\frac{3}{4}\)

\(\Leftrightarrow\left|x+\frac{1}{2}\right|-\frac{31}{2}=\frac{-51}{4}\)

\(\Leftrightarrow\left|x+\frac{1}{2}\right|=\frac{-51}{4}+\frac{31}{2}\)

\(\Leftrightarrow\left|x+\frac{1}{2}\right|=\frac{11}{4}\)

\(\Leftrightarrow\orbr{\begin{cases}x+\frac{1}{2}=\frac{-11}{4}\\x+\frac{1}{2}=\frac{11}{4}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{-13}{4}\\x=\frac{9}{4}\end{cases}}\)

a)    \(\frac{x}{5}=\frac{2}{3}\)

\(\Rightarrow\)\(x=\frac{2.5}{3}=\frac{10}{3}\)

Vậy....

b)   \(\frac{x+3}{15}=\frac{1}{5}\)

\(\Leftrightarrow\)\(5\left(x+3\right)=15\)

\(\Leftrightarrow\)\(x+3=3\)

\(\Leftrightarrow\)\(x=0\)

Vậy....

mấy câu này bạn tích chéo là được 

\(\frac{a}{b}=\frac{c}{d}\Rightarrow a.d=b.c\)  rồi giải bình thường 

a)\(-\frac{15}{12}x+\frac{3}{7}=\frac{6}{4}x-\frac{1}{2}\)

\(\Leftrightarrow\frac{15}{12}x+\frac{6}{4}x=\frac{1}{2}+\frac{3}{7}\)

\(\Leftrightarrow\frac{11}{4}x=\frac{9}{14}\Leftrightarrow x=\frac{36}{154}\)

b) \(\frac{2}{5}\left(x+1\right)-\frac{4}{5}x=0\)

\(\Leftrightarrow\frac{2}{5}x+\frac{2}{5}-\frac{4}{5}x=0\)

\(\Leftrightarrow-\frac{2}{5}x=-\frac{2}{5}\Leftrightarrow x=1\)

dễ mk pn

vy