When you add all the numbers up and then divide by two you get the answer
3 consecutive means
x, x+1, x+2
OR
x, x-1, x-2
the equation based on givens and first equation is:
2(x) + 2(x+1) = 69 - (x+2)
4x + 2 = 67 - x
5x = 65
x = 13
so the largest would be x+2 or 15

Actually Welcome to the Concept of the Functions.
Let's first find the g(-1),
so we get as
3(-1)^2 +5(-1)-6
=> 3 -5-6
=> -8
now since g(-1) =-8
let's find f(g(-1)) that is f(-8)
f(-8) = 4(-8) + 14
=> f(g(-1)) = -32+14
=> f(g(-1)) = -18
-18 is the answer.
2=log(3x+4)
y = loga b a^y = b
since this is base 10
10^2 =3x+4
100 = 3x+4
subtract 4 from each side
96 =3x
divide by 3
32=x