y=-3x-14 (a)
y+5=3(x+3) (b)
First, express both equations in the form: ax+by = c
3x+y = -14 (a)
y+5 = 3x+9
-3x +y = 9-5
-3x+y = 4 (b)
Now we have the system:
3x+y = -14 (a)
-3x+y = 4 (b)
Add both equations to eliminate x:
3x+y = -14 (a)
+
-3x+y = 4 (b)
__________
2y = -10
y= -10/2
y=-5
Then replace y on any initial equation and solve for x:
y=-3x-14
-5 = -3x-14
3x = -14+5
3x = -9
x=-9/3
x= -3
Solution: (x,y) = (-3,-5)