Answer:
x+y=-13......i
xy=42........ii
from ii, x =42/y...iii
put iii in i
42/y +y =-13
(42+y²)/y=-13
42+y²=-13y
y²+13y+42=0
y²+6y+7y+42=0
(y²+6y)+(7y+42)=0
y(y+6)+7(y+6)=0
(y+7)(y+6)
y= -7 or -6
if y=-7,
x-7=-13
x=-6
if y=-6
x-6=-13
x=-7
x= -7,-6
y=-6,-7
