Xavier had some basketball cards. He purchased 7 more. Write an expression describing the total amount he had.

Total amount = b + 7

Step-by-step explanation:

Let the number of basketball cards that he had be represented b

He purchased 7 more.

Hence, an expression describing the total amount he had is written as:

Total amount = b + 7

256π units²   (answer b)

step-by-step explanation:

the formula for the surface area of a sphere of radius r

is             a = 4πr²

and so, if r = 8 units, then the surface area is:

a = 4π(8 units)² = 256π units²   (answer b)