I would really appreciate it if someone could help me out with this problem

Answer:
2018, 2004
Step-by-step explanation:
substitute C(t) for 1274 because it's the cost
1274=6(t-11)^2+980
6(t-11)^2=294
(t-11)^2=49
x-11=7 x-11=-7
x=18, x=4
Answer:
2018, and 2004.
Step-by-step explanation:
do the math "using Your heads".