1) First, look at your given line. The equation of your first line is y = -3x+3. If you compare it to the general slope-intercept form (y = mx+b), you can tell that the slope of this first line is m = -3 (the coefficient of x).
2) Remember that the lines that are parallel to each other all have the same slope. So that means that the line that you're finding the equation for also has a slope of -3.
3) There are several ways to go from here, but since you may be the most familiar with slope-intercept form ((y = mx+b), I'll explain using that formula.
So, start with: y = mx + b
And we'll substitute our slope (m = -3) and our given point (7, -4). We are going to do that so that we can solve for the y-intercept (b value) of our new line.
y = mx + b
-4 = -3(7) + b
-4 = -21 + b
17 = b
So the equation of the line you are looking for is: y = -3x + 17.
