Welcome :: Homework Help and Answers :: Mathskey.com
Welcome to Mathskey.com Question & Answers Community. Ask any math/science homework question and receive answers from other members of the community.

13,435 questions

17,804 answers

1,438 comments

108,773 users

Can you help me?? i just dont really know how do it?

0 votes

what is the first term of an arithmetic sequence with a common difference of -7 and a seventh term of 40??

asked Mar 19, 2013 in ALGEBRA 1 by andrew Scholar

1 Answer

0 votes

Common diference of arithmetic sequence d = -7

nth term of a arithmetic sequence a + (n-1)d

a is the first term of a arithmetic sequence

d is the common term of a arithmetic sequence

n is the number of terms

The seventh term of a arithmetic sequence = 40

a + (n-1)d = 40

Substitute n = 7 , d = -7 and a = a

a + (7-1) -7 = 40

a +(6)(-7) = 40

a - 42 = 40

Add 42 to each side

a - 42 + 42 = 40 + 42

a + 0 = 82

a = 82

There fore thew first term of a arithmetic sequence : a = 82.

answered Mar 23, 2013 by diane Scholar

Related questions

asked Apr 9, 2016 in PRECALCULUS by anonymous
asked Feb 13, 2016 in PRECALCULUS by anonymous
asked Feb 18, 2016 in PRECALCULUS by anonymous
...