My guess by “solutions” is 5 correct points on the line
First let’s do x and y intercepts
X int or when y = 0: 1/3X=12 or x = 36
1. (36,0)
Y int or when x=0: y=12
2. (0,12)
Now let’s isolate y
Y = 12-1/3X
So here we can see obvious solutions are when x = 3 and -3
Y = 12 -1/3(3) = 11 and Y = 12-1/3(-3) = 13
3. (-3,13)
4. (3,11)
Now for the 5th let’s just use x=6 cause -1/3(6) = -2 so y = 10
5. (6,10)
There are five points on the linear line, but that is my interpretation of what you mean by solution. If I’m wrong, let me know.