erza is training for a track race. He starts by sprinting 100 yards. he gradually increases his distance, adding 5 yards a day for 21 days. Which explicit formula models this situation? A. an=100 + (n-1)21 B. an=100 + (n-1)5 C. an=5 + (n-1)100 D. an=21 + (n-1)5

Option B.

Step-by-step explanation:

It is given that erza is training for a track race. He starts by sprinting 100 yards. he gradually increases his distance, adding 5 yards a day for 21 days.  So, the required sequence is

100, 105, 110, 115, ...

It is an AP. Here,

First term = 100

Common difference = 5

Explicit formula for an AP is

where, is first term and d is common difference of the AP.

Substitute in the above formula.

Therefore, the required explicit formula is .

Hence, option B is correct.

step-by-step explanation:

1.3

step-by-step explanation:

3x2=6   9x+6

bring down the 6 on both sides

6+6=12

12= 9x

divide by 9

12/9 =

1.3 =x