The first questions answer:
Given (0, -4), 4x - y = 7. I converted the equation into slope intercept form and I got: y = 4x - 7. Once I had gotten that I put (0, -4) and the equation into Point-Slope Form and solved it: y - (-4) = 4(x + 0), y + 4 = 4x, y = 4x - 4 is the slope intercept form of your equation and point :)