Considering no discounts for bringing people to the theatre, and a being the number of adults attending the show and b the number of children attending the show then:

700 calories
1750 divided by 5 is 350
multiply that by two and you get 700
-8 - 7x is the factored version.
When you arrange the N points in sequence around the polygon (clockwise or counterclockwise), the area is half the magnitude of the sum of the determinants of the points taken pairwise. The N determinants will also include the one involving the last point and the first one.
For example, consider the vertices of a triangle: (1,1), (2,3), (3,-1). Its area can be computed as
(1/2)*|(1*3-1*2) +(2*-1-3*3) +(3*1-(-1)*1)|
= (1/2)*|1 -11 +4| = 3
I can't draw a picture but the little hand would be on the 6 and the big hand would be on the 1.