Try this solution (see the attachment).
we have

Convert to vertex form

we know that
the equation of a vertical parabola in vertex form is equal to

where
(h,k) is the vertex

Group terms that contain the same variable, and move the constant to the opposite side of the equation

Complete the square. Remember to balance the equation by adding the same constants to each side


Rewrite as perfect squares


the vertex is the point 
therefore
<u>the answer is </u>
The y-value of the vertex is 
Answer:
$20,800
Step-by-step explanation:
There are 52 weeks in a year, therefore, do 100 x 52 = $5,200
You earn $5,200 a year, for 4 years so do 5,200 x 4 = $20,800
The percent is %89. Might I suggest using a calculator?
Answer:
n = 9
Step-by-step explanation:
Note that
256 =
, thus
= 
Since the bases on both sides are equal (2) equate the exponents
n - 1 = 8 ( add 1 to both sides )
n = 9