ПОВТОРЕННЯ НАВЧАЛЬНОГО МАТЕРІАЛУ » §.2 (8.1-4)

Розв’яжіть систему рівнянь: 1. x/3 – 2 = 0; x2 + y2 = 37; x – 6 = 0; x2 + y2 = 37; x = 6; 36 + y2 = 37; x = 6; y2 = 1; x = 6; y = 1; x = 6; y = –1; (6; 1). (6; –1). x – y = 9; xy = –20; x = y + 9; y2 + 9y + 20 = 0; y1 = –5 y2 = –4 x = 4; y = –5; x = 5; y = –4; (4; –5). (5; –4). x – y – 4 = 0; 2x2 – 21 = xy; y = x – 4; 2x2 – 21 – x • (x – 4) = 0; 2x2 – 21 – x2 + 4x = 0; x2 + 4x – 21 = 0; x1 = –7; x2 = 3. y = –11; x = –7; y = –1; x = 3; (–7; –11); (3; –1). 4. y2 – 2x2 = 8, x + y = 6, (6 – x)2 – 2x2 = 8. y = 6 – x. 36 – 12x + x2 – 2x2 – 8 = 0. –x2 – 12x + 28 = 0. x2 + 12x – 28 = 0. x1 = –14 x2 = 2 x = –14 y = 20 x = 2 y = 4 (–14; 20) (2; 4)