Answer: The amount of money in his account after 4 years = $7,658.73
Step-by-step explanation:
If interest is compounded annually, then formula to compute amount :
, where P+ principal value, r= rate of interest, n= time ( in years).
As per given,
P= $6700 , r = 3.4% =0.034, n =4

Hence, the amount of money in his account after 4 years = $7,658.73
ANSWER
The vertex of the graph of

is

EXPLANATION
The vertex form of a parabola is given by

where

is the vertex of the parabola.
The function given to us is

This is already in the vertex form.
When we compare this to the general vertex form, we have,


and

Therefore the vertex of the parabola is

Hence the correct answer is option A.
Answer:
well, we only no that
2l + 2w is 80
(lengths and widths on all 4 sides
and that w * l is A
so the function should be w times what's left for l, but also expressed by something with w
2l + 2w = 80 | -2w
2l = 80 -2w | devide by 2
l = 80 - w
now we can substitute l in
A = w * l
so that we only need w's
A(w) = w * (80-w)
for any w it will give us the area, makes only sense for 0<w<80