Verified answer

543

x + y = 10 (1)

x² - y² = 40 (2)

раскладываем (2)

(x - y)(x + y) = 10*(x - y) = 40

x - y = 4

складываем с (1)

2х = 14

х = 7

x + y = 10  y = 3

ответ (7,3)

547

x² - 3y = 22

x + y = 2

y = 2 - x

x² - 3(2 - x) = 22

x² - 6 + 3x - 22 = 0

x² + 3x - 28 = 0

D=9 + 112 = 121

x12 = (-3 +- 11)/2 = 4   -7

x1=4

x+y=2

y=-2

x2=-7

x+y = 2

y = 9

ответ (4, -2) (-7, 9)