[(2x-1)/(3+y+4)]/5=2⇒ (2x-1)/(7+y)=2·5
(2x-1)/(7+y)=10
2x-1=10(7+y)
2x-1=70+10y
2x-10y=70+1
2x-10y=71
3x-y=x+2y+1
3x-x-y-2y=1
2x-3y=1
avem sistemul
{2x-10y=71
{2x-3y=1 inmultim -1
{2x-10y=71
{-2x+3y=-1
2x-2x-10y+3y=71-1
-7y=70 inmultim -1
7y=70
y=70/7
y=10
din 2x-3y=1 rezulta 2x-3·10=1
2x=1+30
x=31/2
x=15,5
