Given the nth term for each arithmetic sequence, how to find the indicated term here?
(1) #a_n=6n+1; a_12#
(2) #a_n=3n-5; a_20#
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"Question #dc117"
1) #a_(color(red)(n)) =6color(red)(n)+1#
For #a_12# where ever there is an #color(red)(n)# write 12 giving:
#a_12=6(12)+1 color(white)("d") ->color(white)("d")a_12=[6xx12]+1=73#
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2) # a_color(red)(n)=3color(red)(n)-5#
For #a_color(red)(20) #where ever there is an #color(red)(n)# write 20 giving:
# a_color(red)(20)=3(color(red)(20))-5color(white)("d")->color(white)("d")a_20=[3xx20]-5=55#
