a b c dễ bạn tự làm nhé : 

d ) \(\frac{72-x}{7}=\frac{x-70}{9}\Leftrightarrow9\left(72-x\right)=7\left(x-70\right)\Leftrightarrow648-9x=7x-490\)

\(\Leftrightarrow1138=16x\Leftrightarrow x=\frac{569}{8}\)

e) \(\frac{2}{x+1}=\frac{5}{3x-2}\Leftrightarrow2\left(3x-2\right)=5\left(x+1\right)\Leftrightarrow6x-4=5x+1\Leftrightarrow x=5\)

\(3^{x+2}-3^x=216\)

   \(3^x.9-3^x=216\)

    \(3^x\left(9-1\right)=216\)

    \(3^x=216\div8\)

    \(3^x=27=3^3\)

\(\Rightarrow x=3\)

\(|2x-1|>\frac{3}{4}\Leftrightarrow\orbr{\begin{cases}2x-1>\frac{3}{4}\\2x-1< \frac{3}{4}\end{cases}\Leftrightarrow\orbr{\begin{cases}2x>\frac{7}{4}\\2x< \frac{7}{4}\end{cases}\Leftrightarrow}\orbr{\begin{cases}x>\frac{7}{8}\\x< \frac{7}{8}\end{cases}}}\)

\(4x=-3y\Leftrightarrow\frac{x}{-3}=\frac{y}{4}\) Áp dụng tính chất dãy tỉ số bằng nhau ta có : 

\(\frac{x}{-3}=\frac{y}{4}=\frac{2x}{-6}=\frac{2x-y}{-6-4}=\frac{3}{-10}\)

\(\Leftrightarrow x=\frac{9}{10};y=-\frac{6}{5}\) ( tự tính nhé ) 

Vậy .........

\(a,7,8:2x=\frac{1}{4}:2\frac{2}{3}\)

\(7,8:2x=\frac{3}{32}\)

\(2x=7,8:\frac{3}{32}\)

\(2x=\frac{416}{5}\)

\(x=\frac{416}{5}:2\)

\(x=\frac{208}{5}\)

\(b,0,25x:3=\frac{5}{6}:0,125\)

\(0,25x:3=\frac{20}{3}\)

\(0,25x=\frac{20}{3}\times3\)

\(0,25x=20\)

\(x=20:0,25\)

\(x=80\)

10x−25−x210x−25−x2

=−(−10x+25+x2)=−(−10x+25+x2)

=−(25−10x+x2)=−(25−10x+x2)

=−(52−2.5.x−x2)=−(52−2.5.x−x2)

=−(5−x)2.=−(5−x)2.

Chúc bạn học tốt!