Решите уравнение х-1/2=3/4х; 1 4/5у=у+4; 3/4у-2/3=7/12у;

1) $x- \frac{1}{2}= \frac{3}{4}x$
$x- \frac{3}{4}x= \frac{1}{2}$
$\frac{1}{4}x= \frac{1}{2}$
$x= \frac{1*4}{2*1}$
$x=2$
2) $\frac{4}{5}y=y+4$
$\frac{4}{5}y-y=4$
$-\frac{1}{5}y=4$
$y= \frac{4*(-5)}{1}$
$y=-20$
3) $\frac{3}{4}y - \frac{2}{3}= \frac{7}{12}y$
$\frac{3}{4}y- \frac{7}{12}y= \frac{2}{3}$
$\frac{9-7}{12}y= \frac{2}{3}$
$\frac{2}{12}y= \frac{2}{3}$
$y= \frac{2*12}{3*2}$
$y=4$