Answer :
To graph you first need to solve
Find your x and y
You need to get you y by its self to do that you subtract 12x on both side it will look like this
12x +9y=15
-12x. -12x
9y=-12x+15 you are now left with y on the left
( you don't really get ride of the number you just move it to the other side and and because the 12 was + it now becomes a -)
9y=12x+15
Now you need to get y completely by its self by division
9y=12x+15
/9 /9
Y = 1.3x+15
Now plug you y in your equation
12x+9(1.3+15)=15
12x+11.7+135=15
12x+146=15
-146 -146
12x = -131
/12x /12x
X= -10.9
12(-10.9) +9y=15
-13.8 + 9y =15
+13.8. +13.8
9y = 18.8
/9. /9
Y= 2.08
So now that you have you x and y you can graph you two points (10.9, 2.08)
12x+9(1.3+15)=15 12x+11.7+135=15 12x+146=15 -146 -146 12x = -131 /12x /12x X= -10.9 12(-10.9) +9y=15 -13.8 + 9y =15 +13.8. +13.8 9y = 18.8 /9. /9 Y= 2.08 hope i helped