What is the square root of 3x plus 16 and equal to 7

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

7. the area of the playing surface at the olympic stadium in beijing isof a hectare. what area will it occupy on a plan drawn to a scaleof 1: 500?

There is an entrance to the computer room at point e which lies on ab and is 5 feet from point a. plot point e on the coordinate plane. find the distance from the entrance at point e to the printer at point e