Write an equation for the nth term of the given geometric sequence. 12, 156, 2028, ..., a
2 answers:
Answer:
a(n) = 12 * (13)^(n-1)
Step-by-step explanation:
First step is to determine what's the scale/multiplication factor between each term:
156 / 12 = 13
2028 / 156 = 13
So, since we got 13 between 1st, 2nd and 3rd term, we can be confident it's the right multiplication factor.
an would be the first term (12) multiplied by a factor of 13. So,
If we try for n > 1, we have
a(2) = 12 * (13)^(2-1) = 12 * 13 = 156
a(3) = 12 * (13)^(3-1) = 12 * 13² = 12 * 169 = 2028
It matches!
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Given:
The phrase is "Wally mowed two more lawns than he mowed last week".
To find:
The expression that models the given phrase.
Solution:
Let the number of lawns mowed by Wally last week be n.
We know that, we use plus sign "+" for "more".
If Wally mowed two more lawns than he mowed last week, then the lawns mowed by the Wally this week is the sum of n and 2.
Lawns mowed this week =
The required expression for the phrase "Wally mowed two more lawns than he mowed last week" is n+2.
Therefore, the correct option is A.