Question 1197683
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Hi 
arithmetic series:  a1=3, and a5=-17
 {{{a[n]=a[1]+(n-1)*d}}}   | Need to Know
 {{{a[5]=3 +(4)*d = -17}}}  d = -5
 {{{a[20]=3+(19)(-5)}}}
    a20 = -92

Wish You the Best in your Studies.
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