Esercizio 1

$\displaystyle 2x-5=7x-3$

$\displaystyle 2x \textcolor{red}{-7x}=-3 \textcolor{red}{+5}$

$\displaystyle -5x=2$

$\displaystyle 5x=-2$ 

$\displaystyle \frac{5x}{\textcolor{red}{5}}=\frac{-2}{\textcolor{red}{5}}$ 

$\displaystyle x=-\frac{2}{5}$

Esercizio 2

$\displaystyle 2x-\frac{5}{3}x=\frac{1}{2} x-3$ ($\textcolor{red}{m.c.m. (2,3)=6}$)

$\displaystyle \frac{12x-10x}{\textcolor{red}{6}} = \frac{3x-18}{\textcolor{red}{6}} $ 

$\displaystyle 6\cdot \frac{12x-10x}{\textcolor{red}{6}} = \frac{3x-18}{\textcolor{red}{6}} \cdot 6$

$\displaystyle 12x-10x = 3x-18 $ 

$\displaystyle 12x-10x-3 x=-18$ 

$\displaystyle – x=-18$ 

$\displaystyle x=18$