Explanation:
We can solve the system by substitution. Since the second equation is already solved for y, we can substitute 3x + 12 for y in the first equation and get:
3x + (3x + 12) = 12
Simplifying this equation, we get:
6x + 12 = 12
Subtracting 12 from both sides, we get:
6x = 0
Dividing both sides by 6, we get:
x = 0
Now that we know x, we can substitute it into either equation to find y. Using the second equation, we get:
y = 3(0) + 12 = 12
Therefore, the solution to the system is (x,y) = (0,12).
Since there is only one solution, the system has one solution.