2. ( x-3 ) + 3. (x+5) > 16

x = 7/5

-1/10+2/5.x+7/20=1/10

-1/10+2/5.x=-1/4

2/5.x=-3/20

x=-3/8

\(-\frac{1}{10}+\frac{2}{5}x+\frac{7}{20}=\frac{1}{10}\)

\(-\frac{1}{10}+\frac{2}{5}x=\frac{1}{10}-\frac{7}{20}\)

\(\frac{2}{5}x=\frac{-1}{4}+\frac{1}{10}\)

\(\frac{2}{5}x=\frac{-3}{20}\)

\(x=\frac{-3}{20}:\frac{2}{5}\)

\(x=\frac{-3}{8}\)

Vậy x = \(\frac{-3}{8}\)

\(3\left(5x+\frac{2}{3}\right)^2=\frac{4}{3}\)

\(\left(5x+\frac{2}{3}\right)^2=\frac{4}{9}\)

\(25x^2+2.5x.\frac{2}{3}+\frac{4}{9}=\frac{4}{9}\)

\(25x^2\frac{20}{3}x=0\)

\(x\left(25x+\frac{20}{3}\right)=0\)

\(\Rightarrow\orbr{\begin{cases}x=0\\25x+\frac{20}{3}=0\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=0\\x=\frac{-4}{15}\end{cases}}\)

\(\left(13\frac{9}{11}\div\frac{38}{49}-5\frac{2}{11}\div\frac{38}{49}\right)\div\left(\frac{49}{38}.\frac{5}{11}\right)\)

\(=\left(\frac{152}{11}\div\frac{38}{49}-\frac{57}{11}\div\frac{38}{49}\right)\div\frac{245}{418}\)

\(=\left(\frac{196}{11}-\frac{147}{22}\right)\div\frac{245}{418}\)

\(=\frac{245}{22}\div\frac{245}{418}\)

\(=19\)

Đề bài thiếu à 

tìm n nguyên để biểu thức nguyên ? 

\(\frac{5n+1}{2n-3}=\frac{10n+2}{2n-3}=\frac{5\left(2n-3\right)+17}{2n-3}=\frac{17}{2n-3}\)

\(\Rightarrow2n-3\inƯ\left(17\right)=\left\{\pm1;\pm17\right\}\)

Ta có : \(\hept{\begin{cases}\left|4x-3\right|\ge0\forall x\\\left|5y+7,5\right|\ge0\forall y\end{cases}}\Rightarrow\left|4x-3\right|+\left|5y+7,5\right|\ge0\)

=> \(F=\left|4x-3\right|+\left|5y+7,5\right|+17,5\ge17,5\)

=> Min F = 17,5

Dấu "=" xảy ra <=> \(\hept{\begin{cases}4x-3=0\\5y+7,5=0\end{cases}}\Leftrightarrow\hept{\begin{cases}x=0,75\\y=-1,5\end{cases}}\)

Vậy Min F = 17,5 <=> x = 0,75 ; y = - 1,5