Question

Find the a26 arithmetic sequence: -15,-35,-55,-75 -515 460 -490

Answer 1

Step-by-step explanation:

QUESTION:-

Find 26th term of the A.P --15,-35,-55,-75...

Solution:-

First term=a=-15

Common Difference=d=-20

We know that

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

$\\ \:\:\:\:\sf {:}\dashrightarrow a_{26}=-15+(26-1)(-20)$

$\\ \:\:\:\:\sf {:}\dashrightarrow a_{26}=-15+25(-20)$

$\\ \:\:\:\:\sf {:}\dashrightarrow a_{26}=-15+(-500)$

$\\ \:\:\:\:\sf {:}\dashrightarrow a_{26}=-15-500$

$\\ \:\:\:\:\sf {:}\dashrightarrow {\boxed{\bf a_{26}=-515}}$