A)
{x-3y=4
{-x+6y=1
[x=4+3y
[-(4+3y)+6y=1
{x=4+3y
{-4-3y+6y=1
[x=4+3y
[3y=5/:3
{x=4+3y
{y≈1,666
[x=4+3*1,666
[y≈1,666
{x≈8,998
b)
{2x-4y=6/:2
{-x+y=1
[x-2y=3
[-x+y=1
{x=3+2y
{-(3+2y)+y=1
[x=3+2y
[-3-2y+y=1
{x=3+2y
{-y=4/*(-1)
[x=3+2y
[y=-4
{x=3+2*(-4)
{y=-4
[x=-5
[y=-4
c)
{2x+3y=4/:2
{x+2y=3
[x+1,5y=2
[x+2y=3
{x=2-1,5y
{2-1,5y+2y=3
[x=2-1,5y
[0,5y=1/:0,5
{x=2-1,5y
{y=2
[x=2-1,5*2
[y=2
{x=-1
{-x+y=1
-2y=5 | :(-2)
y=-2.5
b){2x-4y=6
{-x+y=1 | *2
2x-4y=6
-2x+2y=2
-2y=8 | :(-2)
y=-4
c) {2x+3y=4
{x+2y=3 | * (-2)
2x+3y=4
-2x-4y=-6
-y =-2 | :(-1)
y=2