Follow PEMDAS.
Parenthesis
Exponents
Multiplication & Division
Addition & Subtraction
Alright, do multiplication first, then division. Then, do subtraction then addition.

Hope this helped!
8+2x is the answer. The rest of these characters is for the >20 rule
Answer:
9
Step-by-step explanation:
21^2-19^2=80
sqaure root of 80 to the nearest 10th is
12 - 7 is 5. you can count down 7 times from 12 like: 12, 11, 10, 9, 8, 7, 6, 5.