Przykłady

a) $5x+6-x=2\left(3-x\right)-12$
$5x+6-x=6-2x-12$
$4x+6=-2x-6$
$4x+2x=-6-6$
$6x=-12|:6$
$x=-2$

b) $x\sqrt{5}-5=10-x$
$x\sqrt{5}+x=10+5$
$x\left(\sqrt{5}+1\right)=15|:\left(\sqrt{5}+1\right)$
$x=\frac{15}{\sqrt{5}+1}\cdot \frac{\sqrt{5}-1}{\sqrt{5}-1}=\frac{15\left(\sqrt{5}-1\right)}{{\left(\sqrt{5}\right)}^2-1^2}=\frac{15\sqrt{5}-15}{5-1}$
$x=\frac{15\sqrt{5}-15}{4}$