Equivalent transformation

Linear equations and fractional equations are solved by equivalent transformation.

Linear equations are equations of the form:

$ax+b=0$

Remember

In equivalent transformation, the whole equation is added, subtracted, multiplied, or divided by the same number other than 0 without changing the solution set of the equation.

Example

$x+8=18 \quad|\color{red}{-8}$
$x+8\color{red}{-8}=18\color{red}{-8}$
$x=10$

$5x=25 \quad|\color{red}{:5}$
$\frac{5x}{\color{red}{5}}=\frac{25}{\color{red}{5}}$
$x=5$