2(3х + 9) what the answer plz help​

Astandard american eskimo dog has a mean weight of 30 pounds with a standard deviation of 2 pounds. assuming the weights of standard eskimo dogs are normally distributed, what range of weights would 99.7% of the dogs have? approximately 26–34 pounds approximately 24–36 pounds approximately 28–32 pounds approximately 29–31 pounds

The two square pyramids are similar. find the total volume of both pyramids if the ratio of their surface areas is 9/16

How are algebraic expressions evaluated using substitution?