How many solutions does the system of equations have 3x=-12+15 and x + 4y = 5

infinitely many solutions

Step-by-step explanation:

I assume that you meant

3x = - 12y + 15 and x + 4y = 5 (you accidentally omitted the 'y')

Multiplying the second equation by 3 yields

3x + 12y = 15

... which is identical to the first equation. Thus, the two lines coincide, and we conclude that there are infinitely many solutions.