solve.1:-
Here a = 6 and r = 6 .

a ₄ = 6 *(6) ^{4 –1}
=>a ₄ = 6 *(6) ³
=>a ₄ = (6) ⁴
=>a ₄ = 1296

solve.2:-
Here, first term = 6,
common ratio = 5
then,
8 position is = 6*5 ^{(8 - 1)}
= 6*5 ⁷
= 6*78125
=> 8 position is = 468750 (=t1)

and,
9 position is = 6*5 ^{(9 - 1)}
= 6*5 ⁸
= 6*390625
=> 9 position is = 2343750 (=t2)

and,
10 position is = 6*5 ^{(10 - 1)}
= 6*5 ⁹
= 6*1953125
=> 10 position is = 11718750 (=t3)

and,
11 position is = 6*5 ^{(11 - 1)}
= 6*5 ¹⁰
= 6*9765625
=> 11 position is = 58593750 (=t4)

and,
11 position is = 6*5 ^{(12 - 1)}
= 6*5 ¹¹
= 6*48828125
=> 12 position is = 292968750 (=t5)

so the sequance of numbers from position 8 to 12 are 468750, 2343750, 11718750, 58593750, 292968750