Answered

Find solutions to your problems with the expert advice available on IDNLearn.com. Our experts provide timely, comprehensive responses to ensure you have the information you need.

If the 3rd term of an arithmetic sequence is 2 and the 17th term is -40, find the 7th term

Sagot :

Jcherry99idn

Answer:

-10

Step-by-step explanation:

t3 = a1 + (n - 1)*d

t3 = a1 + (3 -1)*d

2 = a1 + 2d

t17 = a1 + (n - 1)*d

-40 = a1 + 16d                Put the first condition underneath and subtract

  2 = a1 + 2d

-42 = 14 d

d = - 3

2 = a1 + 2*(-3)

2 = a1 - 6                      Add 6 to both sides

2 + 6 = a1

a1 = 8

Now you want the 7th term

t7 = a1 + (n - 1)*d

t7 = 8 + (7 - 1)*d

t7 = 8 + 6*(-3)

t7 = 8 - 18

t7 = - 10

Your participation means a lot to us. Keep sharing information and solutions. This community grows thanks to the amazing contributions from members like you. Thank you for trusting IDNLearn.com with your questions. Visit us again for clear, concise, and accurate answers.