Initial amount is when no change has happened or when t=0
that iniital amoun tis 1
the growth factor
welll, it grows by 40% each time of previous times
I would say growth factor of 1.4
f(x)=a(b)^t
f(t)=1(1.4)^t
initial amount is 1
grouth factor is 1.4
Option D: Two irrational solutions
Explanation:
The equation is 
Subtracting 6x from both sides, we have,

Solving the equation using quadratic formula,

Simplifying the expression, we get,

Taking out the common terms and simplifying, we have,

Dividing by 3, we get,

Hence, the equation has two irrational solutions.
3 x 12 would equal 36, +1 would make it 37. Since there is no space in between 2 and the (, you multiply it. 37 x 3 = 111
So, Jeff should order 111 books