Відповіді §.13 - §.14 » §.14 (4.4)

(2х+y)/(y+x) + 9 • (y-x)/(2x+y) = –6; 2x2 – 7y2 = 100. Заміна (2х+у)/(у-х) = t. t + 9/t = –6. (t^2+ 9+6t)/t = 0. (t + 3)2 = 0. t = –3. (2x+y)/(y-x) = –3. 2x + y = –3(y – x). 2x + y = –3y + 3x; –x = –4y. x = 4y. x = 4y. 2 • (4y)2 – 7y2 = 100; 32y2 – 7y2 = 100. 25y2 = 100. y2 = 4. y = ±2. y = 2. x = 8. y = –2. x = –8. Відповідь: (8; 2); (–8; –2).