Question

if the 10th term of an arithmetic sequence is 15 and the difference is -3, then the first term of the sequence is

Answer 1

Answer:

• First term of the sequence is 42

Explanation:

Given,

10th term of an A.P.(Arithmetic progression) is 15 and the common difference is -3.

Find the first term.

We know,

→ nth term of an A.P. = a + (n - 1)d

Where,

• a denotes the first term.
• n denotes the number of terms.
• d is the common difference

According to the question,

→ 15 = a + (10 - 1)*(-3)

→ 15 = a + 9(-3)

→ 15 = a - 27

→ 15 + 27 = a

→ 42 = a

∴ First term of the A.P. is 42