Question

Which term of the AP: 21, 18, 15, . . . is – 81? Also, is any term 0? Give reason for your answer.


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Answer 1

i hope it will help u alot

Answer 2

QUESTIONS:→

Which term of the AP: 21, 18, 15, . . . is – 81? Also, is any term 0? Give reason for your answer.

ANSWER:→

35th term is -81 & 8th term is 0

STEPS:→

• a(first term) = 21
• d (difference) = 2nd term - 1st term = 18-21 = -3
• an (n^th term )= -81
• n( no of term)=?

so,

• an = a+(n-1) d ( AP formula )
• -81= 21 + (n-1)-3
• -102=(n-1)-3
• -102/-3 = n-1
• 34 = n-1
• 35 = n

if 0 is a term →

• an = 21 + (n-1) -3
• 0 = 21 + (n-1) -3
• -21 = (n-1) -3
• 7 = n-1
• 8 = n