What is the explicit rule for the sequence? -57,-49,-41,- an=8n-49 an=8n-65 an=-8n-49 an=-8n-65

From the sequence given:
 -57,-49,-41,-33...
the common difference, d will be:
-49-(-57)
=8
This implies that the sequence is an arithmetic sequence. The explicit formula is given by:
an=a+d(n-1)
where:
a=first term
d=common difference
n=nth term
from the sequence:
a=-57, d=8
thus the explicit formula for the sequence will be:
an=-57+8(n-1)
simplifying the above we get:
an=-57+8n-8
an=-65+8n
The
An=8n-65

No he does not because he can only cover 12 square feet from 15 square feet which he will still need 3 more. this is because if 3×5=15 square feet and 15-12=3 which thats the answer