The rules for multiplying powers with the same base is you are basically doing the pemdas method Please Excuse My Dear Aunt Sally pemdas
For the first one the nth term is 9n - 8 so the 10th term is 9x10 - 8 = 90-8 = 82
For the second one the nth term is ⅓n + ⅓ so the 11th term is ⅓x11 +⅓ = 3.9999 = 4
Each friend will get approximately 66.6 centimeters of taffy
Answer:

Step-by-step explanation:
Step 1: Simplify square roots
√72 = 6√2
√50 = 5√2
So, 
Step 2: Cancel like terms

Step 3: Rewrite
And we should get our answer!