Question

#3) PLEASE HELP WITH QUESTION, MARKING BRAINLIEST + POINTS :)

Answer 1

$\boxed { \boxed { a_n = a_1 + d(n - 1)}}$

$a_{14} = -33 , a_{15} = 9,$

$a_{14} = a_1 + d(14 - 1) = -33$
$a_1 + 13d = -33$

$a_{15} = a_1 + d(15 - 1) = 9$
$a_1 + 14d = 9$

So the two equations:
$a_1 + 13d = -33$ ----------------- ( 1 )
$a_1 + 14d = 9$     ----------------- ( 2 )

(2) - (1) :
$d = 42$  ----------------- (Sub into 1)

$a_1 + 13(42) = -33$
$a_1 + 546= -33$
$a_1 = -33 - 546$
$a_1 = -579$

$\boxed { \boxed { a_n = -578 + 42(n - 1)}}$