a recursive formula is a function of the previous term. The "an-1" is the term that comes before "an". 
an arithmetic sequence just adds or subtracts the same number (common difference, d) between terms. looking at the recursive formula it is -9 
-35, -44, -53, -62, .....
The explicit formula is a function of the terms place "n" in the sequence. This is written as : 
an = a1 + d(n-1)
fill in 
a1 = -35 and d = -9
an = -35 - 9(n-1)
expand to 
an = -35 - 9n + 9 
an = -26 - 9n