Question

3. Which of term of AP -2,-7,-12.... will be -77?​

Answer 1

Explanation:

By the formula of AP,

$a_{n} = a + (n -1)x$

where a is the first term, n is the number of terms, and x is the constant difference.

So for this question,

$-77=-2+(n-1)(5)$, because the constant difference is 5.

$-77 = -2 + 5 - 5n$

$-77 = 3 - 5n$$-5n = -77 - 3 = -80$

$n = \frac{-80}{-5}= 16$

Answer: Hence, -77 is the 16th term of this AP.