AAG Arithmetic Sequences

Question

Eighth term: 2

Nineteenth term: 101

What are the first 4 terms?

And

80, 76, 72

Determine the numerical position of the term 24 in each arithmetic sequence

Answer 1

a8 = 2

a19 = 101

common difference = (101-2)/(19-8) = 99/11 = 9

a8 =a1 + 9(7) = 2

a1 = 2-63 =-61

a2 = -61+9 =-52

a3 = -52+9 = -43

a4 = -43+9 = -34

1st 4 terms are -61,-52,-43,-34

a20 = 110

a21 = 119

a22 = 128

a23 = 137

a24 = 146

a80 = -61 +9(79)=650

a76 = -61 +9(75)= 614

a72 = -61 +9(71)= 578