After multiplying the first, outside, inside and last terms of two binomials, the next step is A

adding an exponent.

B

adding the four products.

C

dividing the last product.

D

subtracting each term.

14.3

step-by-step explanation:

add all the numbers together.

9 + 12 + 15 + 16 + 17 + 17 = 86

now, divide 86 by how many numbers we have: 6.

86 / 6 = 14.3

the answer is 13 cm

a_n = a_1 + (n - 1)d

the first term is 6.

the common difference d = ?

when you find d, replace n with 7 and d with the common difference to find your answer.