Are variables and constants like terms? true or false?

Bob is putting books on a shelf and takes a break after filling 18 1/2 inches on the book shelf. the book shelf is now 2/3 full. how long is the entire bookshelf?

Can someone factor this fully? my friend and i have two different answers and i would like to know if either of them is right. you in advance. a^2 - b^2 + 25 + 10a

Were only 64 seats. the remaining 6 students had to travel in a separate van. the equation 2b + 6 = 70 represents the given scenario. what does b represent? the number of buses the number of vans the number of students who rode on each bus the total number of students going to the football game