1 стол-x
1 стул-y
{2x+3y=1340
{(x-0,1x)+2 (y-0,2y)=648
{2x+3y=1340|×9
{0,9x+1,6y=648|×20
-{18x+27y=12060
-{18x+32y=12960
-5y=-900:(-5)
y=180
2x+3×180=1340
2x=1340-540
2x=800:2
x=400
1 стол-x
1 стул-y
{2x+3y=1340
{(x-0,1x)+2 (y-0,2y)=648
{2x+3y=1340|×9
{0,9x+1,6y=648|×20
-{18x+27y=12060
-{18x+32y=12960
-5y=-900:(-5)
y=180
2x+3×180=1340
2x=1340-540
2x=800:2
x=400