It's a geometric sequence.

$4,-12,36,... \\ \\
a_1=4 \\
r=\frac{a_2}{a_1}=\frac{-12}{4}=-3 \\ \\
a_n=a_1 \times r^{n-1} \\
a_n=4 \times (-3)^{n-1} \\
a_n=4 \times (-3)^{-1} \times (-3)^n \\
a_n=4 \times (-\frac{1}{3}) \times (-3)^n \\
a_n=-\frac{4}{3}(-3)^n$

It's the sum for term 4 through term 15.

$\boxed{ \sum\limits_{n=4}^{15} (\frac{4}{3}(-3)^n)}$

8 0

2 years ago

Do you think making a table is the best way to find the total area of the rooms

Komok [63]

Well it depends on how many tables you are using and if all the sides of the table are equal lengths....you can it will not hurt anything just make sure you right down all of the area length/width that you cover that way you get the amount you need :) remember to hit that thanks button please:)

6 0

3 years ago