y = 4x -21 (again cool name btw) :)
y=4x-3 has slope = to the coefficient of the x term = 4
all parallel lines have the same slope.
y=4x + b, where b can be any real number, so just plug in the point (4,-5) into the general equation
y=4x+b = -5 = 4(4) + b
-5 = 16 + b
-21 = b
b = -21 = the y intercept, so the equation is
y=4x -21