I just need no. 12 done
2 answers:
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(a) The explicit rule to model the sequence formed by the number of seats in each row is
(b) The 35th row has 120 seats
Step-by-step explanation:
The rule of the nth term of an arithmetic sequence is
, where
- a is the the first term
- d is the common difference between each two consecutive terms
∵ There are 18 seats in the 1st row
∵ There are 21 seats in the 2nd row
∵ 21 - 18 = 3
∵ The number of seats is increased by 3 with each additional row
- The number of seats in each row represents an arithmetic
sequence because there is a common difference between
each two consecutive rows
∴ The number of seats in each row formed an arithmetic sequence
∵ The number of seats in the first row = 18 seats
∴ a = 18
∵ The number of seats in a row continues to increase by 3 with each
additional row
∴ d = 3
- Substitute the values of a and d in the rule of nth term
∴
- Simplify the right hand side
∴
- Add like terms
∴
(a) The explicit rule to model the sequence formed by the number of seats in each row is
∵ There are 120 seat in a row
- Substitute by 120 in the rule above
∴ 120 = 15 + 3n
- Subtract 15 from both sides
∴ 105 = 3n
- Divide both sides by 3
∴ n = 35
∴ The number of the row is 35
(b) The 35th row has 120 seats
Learn more:
You can learn more about the sequences in brainly.com/question/7221312
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