1) Find the indicated term of the arithmetic sequence with the first term a1 and the common difference d. ?

a. a. Find a7 when a1 = –8 and d = 4.
b. b. Find a16 when a1 = 10 and d = 7.

1 Answer
Apr 14, 2018

#color(orange)([a] a_7=16#

#color(orange)([b] a_16=115#

Explanation:

#a]# Find #a_7# when #a_1 = –8# and #d = 4#:

Formula:-

#color(blue)(a_n=a_1+(n-1)d#

So we have, #color(darkred)(=>a_7=(-8)+(7-1)4#

#a_7=(-8)+(6xx4)#

#=>a_7=(-8)+24#

#color(red)(=>a_7=16#

#therefore# The #color(magenta)(7^(th)# term is #color(magenta)(16.#

#b]# Find #a_16# when #a_1 = 10# and #d = 7:#

Formula:-

#color(blue)(=>a_n=a_1+(n-1)d#

So we have, #color(darkred)(a_16=10+(16-1)7#

#=>a_16=10+(15xx7)#

#=>a_16=10+105#

#color(red)(=>a_16 =105#

#therefore #The #color(magenta)(16^(th# term is #color(magenta)(115.#

~Hope this helps! :)