a: \(\frac{x}{27}=-\frac{2}{3.6}\)
=>\(\frac{x}{27}=-\frac{10}{18}=-\frac59\)
=>\(x=-\frac59\cdot27=-15\)
b: \(7:\left(-49\right)=x:\left(-28\right)\)
=>\(\frac{x}{28}=\frac{7}{49}=\frac17=\frac{4}{28}\)
=>x=4
c: \(0,3:\left(-2,5\right)=1,5:\left(-x\right)\)
=>\(\frac{1.5}{x}=\frac{0.3}{2.5}\)
=>\(x=1,5\cdot2,5:0,3=5\cdot2,5=12,5\)
d: \(\frac{x-5}{2x-25}=\frac{-2}{3.6}\)
=>\(\frac{x-5}{2x-25}=\frac{-10}{18}=\frac{-5}{9}\)
=>-5(2x-25)=9(x-5)
=>-10x+125=9x-45
=>-19x=-45-125=-170
=>\(x=\frac{170}{19}\)
e: \(\frac{x-5}{0,08}=\frac{2}{x-5}\)
=>\(\left(x-5\right)^2=0,08\cdot2=0,16\)
=>\(\left[\begin{array}{l}x-5=0,4\\ x-5=-0,4\end{array}\right.\Rightarrow\left[\begin{array}{l}x=0,4+5=5,4\\ x=-0,4+5=4,6\end{array}\right.\)
f: \(\frac{x-1}{3}=\frac{2x+1}{3,2}\)
=>3(2x+1)=3,2(x-1)
=>6x+3=3,2x-3,2
=>2,8x=-3,2-3=-6,2
=>\(x=-\frac{6.2}{2.8}=-\frac{31}{14}\)
g: \(\frac{\left|x-5\right|}{1,2}=\frac{8}{2,4}=\frac{4}{1,2}\)
=>|x-5|=4
=>\(\left[\begin{array}{l}x-5=4\\ x-5=-4\end{array}\right.\Rightarrow\left[\begin{array}{l}x=4+5=9\\ x=-4+5=1\end{array}\right.\)
h: \(\frac{4\frac14}{2\frac78}=\frac{x-4}{1,61}\)
=>\(\frac{x-4}{1,61}=\frac{17}{4}:\frac{23}{8}=\frac{17}{4}\cdot\frac{8}{23}=\frac{17\cdot2}{23}=\frac{34}{23}\)
=>\(x-4=1,61\cdot\frac{34}{23}=2,38\)
=>x=2,38+4
=>x=6,38(nhận)
