3 years ago

What is the first term for an arithmetic sequence with a12 = 56 and a21=101?

1 answer:

4 0

The first term is -43.

Explanation:

an = a + (n - 1)d

a12 = a + 11d = 56, first equation
a21 = a + 20d = 101, second equation

Subtract the second equation from the first equation, cancelling +a and -a
11d - 20d = 56 - 101
-9d = -45
d = 5

Subtitute d into the first equation
a + 99 = 56
a = -43

a refers to the first term, hence the first term is -43.

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Marcos mom gave him d dollars for his allowance one week. he also earned $14.55 for his newspaper route that week. How much mone

vekshin1

Marco has ( d + 14.55 ) $

Step-by-step explanation:

Marco's mom gave him d dollars for his allowance one week.

Allowance of one week = d $

He also earned $ 1 4 . 5 5 for his newspaper route that week.

Earning of Marco by selling newspaper route that week = 14.55 $

Total earning = Allowance of one week + Earning of Marco by selling newspaper route that week

Total earning = ( d + 14.55 ) $

So Marco has ( d + 14.55 ) $