Answers

2016-06-28T19:31:03+08:00
Step I: let try in 2nd term
an=a1+(n-1)d
a2=a1+(2-1)-20
35=a1+(-20)
35=a1-20
35+20=a1
55=a1
therefore, the first term is 55

Step II: solve for the last or 5th term
an=a1+(n-1)d
a5=a1+(5-1)-20
a5=55+(4)-20
a5=55-80
a5=-25
2 4 2