5 + 8s = 15 + 3s
8s - 3s = 15 - 5
5s = 10
s = 10/5
s = 2 <=== they will charge the same at 2 sq ft
The wording of this question is a bit confusing... You can't write a sequence in sigma notation, but rather a series or sum. I think the question is asking you to write the sum of the sequence,

which would be

in sigma notation.
To do this, notice that the denominator in each term is a power of 2, starting with
and ending with
. So in sigma notation, this series is

Answer:
f(5) = 4375
Step-by-step explanation:
Given f(n) = 5f(n - 1) and f(1) = 7
This allows us to find the next term in the sequence from the previous term
f(2) = 5f(1) = 5 × 7 = 35
f(3) = 5f(2) = 5 × 35 = 175
f(4) = 5f(3) = 5 × 175 = 875
f(5) = 5f(4) = 5 × 875 = 4375
Answer:
BC= 20 units
Step-by-step explanation:
Since ∆ ABC is an equilateral triangle, all the sides are equal in length.
AC= BC
=>-y+23= 6y+2
=>-y-6y= 2-23
=>-7y= -21
=>y= 21/7
=>y= 3
BC = 6y+2 = 6(3)+2 = 18+2 = 20 units