it should be -2,4 or -5,1.
since both answers = y then you put them equal to each other and then solved for x.
x+6=x^2 +8x +16
0=x^2 +7x +10
0=(x+2)(x+5)
x=-2 or -5
and for y I input the two separately into one of the equations
y= (-2)+6
y=4
y=(-5)+6
y=1
and then I double checked by imputing my y's and x's into the remaining equation.
(4)=(-2)^2 +8(-2)+16
4=4-16+16
4=4
(1)=(-5)^2 +8(-5)+16
1=25-40+16
1=1
I hope your tests go well with the help of this knowledge.