# Math Help - Solving

1. ## Solving

Solve the following:
a) 22x-2(2x)=3
b) a bacterial culture starts with 1500 bacteria. After 5h, the estimated count is 35 000. What is the doubling period?
c) When the function f(x)=ax3+7x2+bx-8 is divided by (x+1) it has a remainder of 18; and (x-2) is a factor. Determine a and b.

2. ## Re: Solving

(a) let $u = 2^x$ ... can you solve $u^2 - 2u = 3$ ?

(b) $y = y_0 e^{kt}$

$35000 = 1500e^{k \cdot 5}$

solve for the growth constant $k$, then determine the time $t$ when $y = 3000$

(c) $f(-1) = 18$ and $f(2) = 0$ ... why?

you should get two equations with two unknowns ... solve for a and b