Can someone help me

Cindy uses 1-inch cubes to find the volume of a jewelry box shaped like a rectangular prism. she uses 780 cubes to completely fill the jewelry box with no gaps or overlaps. if the jewelry box is 13 inches long and 5 inches wide, how tall is cindy’s jewelry box?

What number must you add to complete the square x^2+12x=16

Find the simple interest earned to the nearest cent for each principal,interest rate,and time 735 7% and two and a half years