Решить систему уравнений: y-x=6 ; 1/x-1/y= 1/12

{y-x = 6
{1/x - 1/y = 1/12

{y-x = 6
{(y-x)/xy = 1/12

{y-x = 6
{xy = 72

{y = x+6
{x² + 6x - 72 = 0

D = 36 + 288 = 324
x1 = (-6-18)/2 = -12 => y1 = -6
x2 = (-6+18)/2 = 6 => y2 = 12

ответ: (-12; -6); (6; 12)