Answer:
it have two parallel sides
Using elimination method. Using substitution will cause some fraction problems.
c- child tickets
a- adult tickets
4a + 7c = $83
5a + 6c = $90
multiply by -5
-20a - 35c = -$415
20a + 24c = $360
-11c= -$55
c = $5 child tickets
4a + 7(5)= $83
4a + 35 = $83
4a = $48
a= $12 adult tickets
My graphing calculator says g(4) = f(2).
The 4th selection, x=4, is appropriate.