Simplify 7 (B + 3) + 2B.

9B + 3

9B + 10

9B + 21

Expand

(7B + 21 + 2B)

Collect like terms

(7B + 2B) + 21

Simplify

9B + 21

Answer: C) or the third option.

Remember, we can add like terms

also remember the commutative property of addition which is

you can move the order around when adding or a+b=b+a

also, distributive property which is a (b+c) = ab+ac

so

distribute first

7 (B+3) = 7 (B) + 7 (3) = 7B+21

now we have

7B+21+2B

by the commutative property

7B+2B+21

adding like terms

9B+21

answer is 9B+21