412 ÷ 20 = 20 boxes with 12 remaining.
Total boxes needed = 20 + 1 = 21
Answer: 21 boxes will be needed.
A im getting outta my version

take the derivitive to find the slope


so at x=1, the slope is f'(1)=6(1)^2-4=6-4=2
y=mx+b
y=2x+b
find b
at x=1, f(1)=2(1)^3-4(1)=2-4=-2=y
-2=2(1)+b
-2=2+b
-4=b
equation is y=2x-4
5 small cards ($12) and 3 large cards ($11.85) and the total of both ($12 + $11.85) = $23.85
F + V - E = 2....solving for F
V = 16
E = 37
just a matter of subbing and solving
F + 16 - 37 = 2
F - 21 = 2
F = 2 + 21
F = 23