Using the equation P=a+b+c , you just need to plug in.
4a-2b + 7a-3 + 9a - 4
Combine like terms.
20a-2b-7
The graph of y = (-3x)^2 is much narrower than it's original graph, but still keeps all of the other properties of it's parent parable y = x^2. The new graph's with is that of the original parabola's with divided by 3.
Please see the attached image for a visual representation of our scale factor. We can set up this proportion by taking the DVD cover and poster values and placing them in fractions. Cross multiply and divide to solve for x.