Help, please! An explanation would be great, I'm so confused on this question-

a = 250

b = 10

Step-by-step explanation:

1) a =

Putting x = 10

a = 5(10)²/2

a = 5(100)/2

a = 250

2) b =

Putting x = 10

b = 2(10)²(10-5) / 10(10)

b = 2(100)(5) / 100

b = 1000 / 100

b = 10

to determine the unit cost your would divide the total cost by the number sold.

7 bagels for $4.41       $4.41/7 = $.63 each at fresh side

5 bagels for $3.60         $3.60/5 = $.72 each at value mart