Question 705639
The -3 equation transforms easily to x+y=-1, and the "17" equation becomes -5x-y=17.


Summary of System:
-5x-y=17
x+y=-1


Add both equations:  -4x+0=16; therefore, x=-4.
Substitute the value into either equation.
-4+y=-1
y=+4-1
y=+3
Answer: point (-4,3)


When you check, you found both answers as correct?
Let's try the other point you or the friend found, (-4,5):
-5*(-4)-(5)=17?
20-5=17?
15=17?  NO.