You have 3 unknowns: a, b, and c. That means you have to have 3 equations to solve for the values of them. 3 unknowns needs 3 different equations. We will use the first 3 points in the table and thank God that one of them has an x value of 0. We will replace the x and y in the general form of the quadratic with the x and y from the table, 3 times, to find each variable. Watch how it works. We will start with (0, 15). 
. That gives us right away that c = 15. We will do the same thing again with the second value in the table along with the fact that c = 15 to get an equation in a and b. 
which simplifies to 4a+2b=.5. Now do the same for the third set of coordinates from the table. 
which simplifies down to 16a+4b=2. Solve those simultaneously. Multiply the first bolded equation by -4 and then add that one to the second bolded one. 
gives us -16a-8b=-2. Add that to the second bolded equation and the a terms cancel out giving us -4b=0 so b = 0. Subbing that back in we solve for a: 16a+4(0)=2 and 16a = 2. Therefore, a = 1/8. The quadratic then is 
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Answer:
482 km
63.94 degrees
Step-by-step explanation:
to solve this question we will use the cosine rule. For starters, draw your diagram. From point A, up north is 500km and 060 from there, another 300. If you join the point from the road junction back to the starting point, yoou have a triangle.
Cosine rule states that
C =
where both A and B are the given distances, 500 and 300 respectively, C is the 3rd distance we're looking for and c is the given angle, 060
solving now, we have
C =
C =
C =
C =
C =
C = 482 km
The bearing can be gotten by using the Sine Rule.
=
sina/500 = sin60/482
482 sina = 500 sin60
sina =
sina = 0.8983
a = sin^-1(0.8983)
a = 63.94 degrees