Verified answer

x-y=7

xy=-12

x=7+y

xy=-12

(7+y)y=-12

7y+y²=-12

y²+7y+12=0

y²+3y+4y+12=0

y(y+3)+4(y+3)=0

(y+4)(y+3)=0

y=-4 ∨ y=-3 

x=7+(-4) ∨ x=7+(-3) 

x=3 ∨ x=4 

Verified answer

х = 7 + у

у(у+7) = -12

у²+7у+12 = 0

Д = 49-48=1

у1 = (-7-1)/2 = -4

у2 = (-7+1)/2 = -3

у = -4       или      у = -3

х = 3                   х = 4

Ответ. (3, -4); (4, -3).