The product of 10 and the diffrence of a number x and 14is 90

The late fee for library books is $2.00 plus 15¢ each day for a book that is late. if maria’s fee for a late book was $3.20, write and solve a linear equation to find how many days late the book was.

1) prove that 731^3−631^3 is divisible by 100 2) prove that 99^3−74^3 is divisible by 25

8litres of paint can cover 129.6 m². how much paint is required to paint an area of 243m²?