(z+v)/6 - (z-v)/3 = 1,
(2z-v)/6 - (3z+2v)/3 = -13,
z+v - 2(z-v) = 1*6,
2z-v - 2(3z+2v) = -13*6,
z+v - 2z + 2v = 6,
2z-v - 6z - 4v = -78,
3v - z = 6,
-5v - 4z = -78,
из 1 ур-ия:
z = 3v - 6,
подставим во 2 ур-ие:
-5v - 4*(3v - 6) = -78,
-5v - 12v + 24 = -78,
-17v = -78 - 24,
-17v = -102,
v = 6,
z = 3*6 - 6 = 18 - 6 = 12,
ответ: v = 6, z = 12