Does anyone know this problem?

Bring the fraction a/a-4 to a denominator of 16-a^2

Car a and car b were in a race .the driver of car b claimed that his car was twice as fast as car a

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