Question

Use the explicit formula an = a1 + (n - 1) • d to find the 350th term of the sequence below. 57, 66, 75, 84, 93, ... A. 3234 B. 3207 C. 3141 D. 3198

Answer 1

To use the equation we need a1 and d(the common difference).
We have a1 = 57, we need to find d.
93-84 = 9; 84-75=9; 75-66=9; 66-57=9
d = 9
a350 = 57 + (350-1)(9)
a350 = 57 + (349)(9)
a350 = 57 + 3141
a350 = 3198

Answer 2

Hello : 
57 ,    66  , 75  , 84  , 93 is the arithmetic sequence 
the common difference is : d= 93-84=84-75 =75-66 =66-57 = 9
by formula : an = a1 + (n - 1) • d
n= 350
a350 = 57 +(350-1)(9)=3198.... (answer: D. 3198)