решите систему способом сложения:
(х/12 + у/5=8
(х/4-у/7=-2

(х/12+у/5=8(х/4+у/7=-2х/12 + 3х/12 + 7у/35 + 5у/35 = 64х/12 + 12у/35 = 64х/12 = 210/35 - 12у/354х/12 = 210-2у/354х/12 = 6-12у | ×1248х=72-144у48х+144у=72 | ÷48х+2у=1,5х = 1,5 - 2у_______(1,5-2у)/4 + у/7 = -210,5-14у/28 = - 56/2810,5-14у+4у = -5610,5-10у=-56-10у=-66,5у=6,65____х= 1,5-2×6, 65 = 1,5-13,3=-11,8(-11,8; 6,65)