To solve this system of equations, start by plugging your equation for x wherever x appears in your second equation, giving you (y-3)+3y=13. Now, combine like terms, (y-3)+3y=13 => 4y-3=13, solve for y by adding 3, 4y-3=12 => 4y=16, divide by 4, 4y=16 => y=4. Now that you have your y value, plug it into the equation for x to get the x value, x=y-3=4-3=1. This makes your solution (1,4), answer choice A