If 12a 3b=1 and 7b–2a=9 what is the average of a and b.

Tamera puts 15/4 gallons of gasoline in her car. which mixed number represents the gallons of gasoline? a) 2 3/4 gallons b) 3 1/4 gallons c) 3 3/4 gallons d) 4 1/2 gallons answer it's worth a lot of points!

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

A. what is the area of the base? use complete sentences to explain your reasoning. b. what is the volume of the prism? use complete sentences to explain your reasoning.