# The sum of the first 10 terms of an arithmetic sequence is 530.what is the first term if the last term is 80? what is the common difference

2
by luckypussy

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by luckypussy

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sn=530

an=80

n=10

a1=?

d=?

*Finding value of a

530=10/2(a1+80)

530=5(a1+80)

530=5a1+400

530-400=5a1

130=5a1

a1=26

Finding the difference we use the formula an=a1+(n-1)d

80=26+(10-1)d

80=26+9d

80-26=9d

54=9d

d=6

The a1=26 an d=6

:)