K11

a)
$3x+6=0$
$3x=-6\ \parallel:3$
$x=-2$
b)
$4x-5=2x+6$
$4x-2x=6+5$
$2x=11\ \parallel:2$
$x=5{,}5$
c)
$\left(3x-2\right)\left(2x-1\right)=0$
$6x^2-7x+2=0$
$x=\frac{-b\pm\sqrt{b^2-4ac}}{2a}=\frac{7\pm\sqrt{\left(-7\right)^2-4\cdot6\cdot2}}{12}=\frac{7\pm\sqrt{49-48}}{12}=\frac{7\pm1}{12}=\frac{6}{12}=\frac{1}{2}\ tai\ \frac{8}{12}=\frac{2}{3}$
$\left(3x-2\right)\left(2x-1\right)=2$
$6x^2-7x=0$
$x\left(6x-7\right)=0$
$x=0\ tai\ 6x-7=0$
$6x=7\ \parallel:6$
$x=1\ \frac{1}{7}$