M-4/9m=45 84/108=2y-0,5 4,5

M- $\frac{4}{9}m$ = 45
$\frac{9}{9}m$ - $\frac{4}{9}m$ =45
$\frac{5}{9}m$ = 45
m=45: $\frac{5}{9}$
m= $\frac{45*9}{5}$
m= $\frac{9*9}{1}$
m=81

$\frac{84}{108} =2y- \frac{0,5}{4,5}$
$\frac{4*21}{4*27} =2y- \frac{0,5}{0,5*0,9}$
$\frac{21}{27} =2y- \frac{1}{9}$
2y= $\frac{21}{27} + \frac{1}{9} = \frac{21}{27} + \frac{3*1}{3*9} = \frac{21}{27} + \frac{3}{27} = \frac{24}{27} = \frac{3*8}{3*9} = \frac{8}{9}$
2y= $\frac{8}{9}$
y= $\frac{8}{9}$ :2
у= $\frac{8}{9*2}$
у= $\frac{4}{9}$