You can solve this by substitution:
x + y = -6
y = -6-x
Substitute for y in xy = -7:-
x(-6 - x) = -7
-x^2 - 6x = -7
x^2 + 6x - 7 = 0
(x + 7)(x - 1) = 0
so x = -7, 1
To find the values of y plug these va;ues of x into the equation x + y = -6:-
when x = -7, y = -6 + 7 = 1
when x = 1, y = -6 - 1 = -7
so answer is x = -7 and y = 1
and x = 1 and y = -7
