B = 1/4c + 14
d = 5/4c - 2
b = d
1/4c + 14 = 5/4c - 2 ....multiply by 4
c + 56 = 5c - 8
56 + 8 = 5c - c
64 = 4c
64/4 = c
16 = c <== Chris
b = 1/4c + 14.....b = 1/4(16) + 14.....b = 4 + 14....b = 18 <== Brian
d = 5/4c - 2....d = 5/4(16) - 2.....d = 20 - 2.....d = 18 <== Damien
solution : Brain and Damien answered 2 more questions correctly then Chris did. <===
400 - 2 x Age = 244
-2*Age = -156
Age = 78 years
Answer: The vertex is x=-7/6
*The graph is below*
Hope that this helps!