Question

In an Ap, if the common difference (d) = _4, and the seventh term (a7) is 4,then find the first term

Answer 1

Answer:

$\large{\underline{\boxed{\sf First \: term = 28}}}$

Step-by-step explanation:

Given that ;

Common difference (d) = (-4)

Seventh term, a₇ = 4

To find: The first term

Solution:

We know that ;

$\sf a_n = a + (n - 1)d$

Here, n = 7, a = first term, and d is the common difference.

$\sf a_7 = a + (7 - 1) \times ( - 4) \\ \\ \implies \sf 4 = a + 6( - 4) \\ \\ \implies \sf 4 = a - 24 \\ \\ \implies \sf a = 24 + 4 \\ \\ \implies \sf a = 28$

Hence, the first term of an A.P is 28.