{4(3x+y)-1=y-2x
{2(4x-y)+19=-x
{12x+4y-1=y-2x
{8x-2y+19=-x
{12x+4y-y+2x=1
{8x-2y+x=-19
{14x+3y=1|*2
{9x-2y=-19|*3
+{28x+6y=2
+{27x-6y=-57
55x=-55|:55
x=-1
-1*14+3y=1
3y=1+14
3y=15|:3
y=5
{15+2(x+3y)=3(4x+y) {2(5x-y)-3y=2+3(2x+y)
{15+2x+6y=12x+3y
{10x-2y-3y=2+6x+3y
{2x+6y-12x-3y=-15
{10x-2y-3y-6x-3y=2
{-10x+3y=-15|*2
{4x-8y=2|*5
+{-20x+6y=-30
+{20x-40y=10
-34y=-20|:(-34)
y=10/17
-10x+3*10/17=-15
-10x=-15-1 13/17
-10x=-16 13/17|:(-10)
x=285/17*1/10=57/34