Solve em for me please

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?

Complete the solution of the equation. find the value of y when x equals to 1 9x-5y=29

Do you mind if you guys me with this question i’m on number 8