Cześć!
1)
Wyznaczam x
[tex]2x-4y=12\\\\2x=4y+12 \ \ /:2\\\\\boxed{x=2y+6}[/tex]
Wyznaczam y
[tex]2x-4y=12\\\\-4y=-2x+12 \ \ /:(-4)\\\\\boxed{y=0,5x-3}[/tex]
2)
[tex]2a=3b+4 \ \ /:2\\\\\boxed{a=1,5b+2}[/tex]
3)
[tex]16=\frac{a+b}{4} \ \ /\cdot4\\\\a+b=64\\\\\boxed{a=64-b}[/tex]
