Решить систему уравнений {x+y=-7

{xy=6

(-7-y) * y = 6

-7y-y^2 - 6 = 0

D = 49-4 * (-1) * (-6) = 25

y1 = 7-sqrt (25) / 2 * (-1) = - 1

y2 = 7+sqrt (25) / 2 * (-1) = - 6

x1 = - 7+1 = - 6

x2 = - 7+6 = - 1

извиняюсь забыла вот это в самом начале: x = - 7-y

x = - 7-y

(-7-y) * y = 6

-7y-y^2 - 6 = 0

D = 49-4 * (-1) * (-6) = 25

y1 = 7-sqrt (25) / 2 * (-1) = - 1

y2 = 7+sqrt (25) / 2 * (-1) = - 6

x1 = - 7+1 = - 6

x2 = - 7+6 = - 1