Answer:
4 ft.
Step-by-step explanation:
We can consider the orignial square's sides to be x, so area of the original figure: 
The new rectangle's sides will be x and x+8, so the area of the new figure will be x^2+8x.
We know that the new area is 3 times the old one. So our equation will be:
x^2+8x=3x^2
our answer will be x=4.
Therfore, the length of the side of the old flower bed is 4 ft.
According to the question,
Let,
"n" represent the number of miles semir walked.
"y" represent the number of miles sarah walked.
Now, according to the question,
y = 2n - 5 ........................this is your equation
Also,
the question states, each of them collect $18 in pledges for every miles walked.
Given,
Sarah collected $450
Now,
Using unitary method,
Sarah collects $18 for 1 mile
Sarah collects $1 for (1 / $18) mile
Sarah collects $450 for (1 / 18) * 450 mile
= 25 miles
So, Sarah walks 25 miles.
Now,
Taking equation,
y = 2n - 5
Since, y is the no. of miles sarah walked, we can write 25 in place of "y" So,
(25) = 2n - 5
25 + 5 = 2n
30 = 2n
30 / 2 = n
15 = n
Since, "n" is the no. of miles that semir walked, Semir walked 15 miles.
An = a1 + (n-1)d
an = 27 + (n-1)(-6)
(-7)*(2/5 + (-3/7))
= -14/5 + 3
=1/5
Given:
A triangle ABC.
The given expression for b is:

To find:
The expression that is equivalent to b.
Solution:
According to the Law of Cosines,

It can be written as:
...(i)
We have,
...(ii)
On comparing (i) and (ii), we get




Therefore, the required values are
.