$S_{n} = \frac{n}{2} (4n + 20) \\ \\S _{n - 1} = \frac{(n - 1)}{2} (4n - 4 + 20) \\ \\ S _{n - 1} = \frac{(n - 1)}{2} (4n + 16) \\ \\S _{n - 1} = \frac{(n - 1)(4n + 16)}{2} \\ \\ { \boxed{S _{n - 1} = {2 {n}^{2} + 6n - 8}}} \\$

(b).

from general equation:

$S _{n - 1} = \frac{(n - 1)}{2} (4n + 16)$

first term is 4n

common difference:

$16 = \{(n - 1) - 1 \}d \\ 16 = (n - 2)d \\ d = \frac{16}{n - 2}$

8 0

2 years ago

Mrs. Clemmons math class went outside and plucked blades of grass and then measured them. The line plot shows what fraction of a

kolezko [41]

Ask @A+Smart Hope this helpsssssss

7 0

2 years ago

How do you Simplify (y^12)^5

goldenfox [79]

Answer:

y^60

Step-by-step explanation:

(a^b)^b= a ^ b times b

12 times 5 is 60 so it's y^60

sorry my explaination is so complicated but im confident in the answer

8 0

2 years ago

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