What is 3 times 5 i need help for math class

If m 17 27 90 63 ** picture is attached

17 in long 1.3 ft wide and 8in high what is the volume

To solve the system of equations below, pedro isolated the variable y in the first equation and then substituted it into the second equation. what was the resulting equation? { 5y=10x {x^2+y^2=36