{(2x+1)/3 - (x-2y)/5 = ( 4(2x+y) ) / 15
{(x - 4y)/3 + (5x - 11y)/6 = (3x -1)/4
{ (5(2x+1) - 3(x-2y) ) /15 = (8x+4y)/15 | *15
{ (2(x- 4y) + (5x-11y) ) / 6 = (3x-1)/4 | *12
{ 5(2x+1) - 3(x-2y) = 8x +4y
{ 2* (2x-8y +5x - 11y) = 3(3x-1)
{10x + 5 - 3x + 6y = 8x + 4y
{ 2*(7x-19y ) = 9x - 3
{7x + 6y + 5 = 8x + 4y
{14x - 38y = 9x - 3
{7x +6y - 8x -4y = - 5
{ 14x -38y - 9x = - 3
{-x + 2y = -5 ⇒ 2y +5 = x
{5x -38y = -3
5 (2y +5) -38y =-3
10y +25 - 38y = -3
-28y = -3-25
-28y = -28
y=1
x= 2*1 + 5
x=7
ответ: (7; 1)