All you have to do is go to the location of the number and go over the other location of the other number
1/2 would be in between 0 and 1. The fraction 4/2 is actually 2, so it would just be plotted on the number 2 on the number line. 5/2 is reduced to 2.5, therefore it goes in between 2 and 3.
Focus of the parabola is (-5,5) and directrix is y = -1.
Let's assume a point (x,y) on parabola.
According to definition of parabola, the distance between point (x,y) and focus (-5,5) would be same as the distance between the point (x,y) and directrix y = -1.

Hence, option D is correct, i.e. f(x) = one twelfth (x + 5)2 + 2.
The answer is 300 divided by 20 which you would get 15.
I don't believe you can. It would end up being 1/2 for all the terms so just leaving it as a fraction would be neater.