Because it has the same slope, both equations must have 5x as their slope. The 2 equations are not going to have the same y intercept, so the +3 can be ignored and replaced with b. You want to plug in (1,5) into you new equation of y=5x+b, to get 5=5(1)+b. Multiply 5 by 1 to get 5, and then subtract 5 from both sides, which gives you 0=b. This means that the y intercept is the origin, so your new equation is y=5x
