САМОСТІЙНИ РОБОТИ » Ср.10 (8)

Розв’яжіть систему рівнянь x2 + xy = –7 y2 + xy = 56 x2 + 2xy + y2 = 49 (x + y)2 = 49 x + y = ±7 x + y = 7 x2 + y2 = –63 x + y = –7 x2 – y2 = –63 x + y = 7 (x + y)(x – y) = –63 x + y = –7 (x – y)(x + y) = –63 x2 – y2 = –63 x + y = 7 7(x – y) = –63 x + y = –7 –7(x – y) = –63 x + y = 7 2x = –2 x – y = –9 x = –1 x + y = –7 2x = 2 x – y = 9 x = 1 x = –1. y = 6 . (–1; 6). x = 1. y = –8. (1; –8).