please help I need to write the equation in slope-intercept form

y=4x-3;(-3,12)

I will assume you want an equation which is parallel to the given line and passing through (-3,12)

Then new line will have the same slope, so it will differ from the given line only in its y-intercept:

new line:
y = 4x + b
but (-3,12) lies on it, so
12 = 4(-3) + b
b = 24

y = 4x + 24

If the new line is perpendicular to the given one,
y = (-1/4)x + b
then proceed as I did.