The square root of 9x plus 7 plus the square rot of 2x equall to 7

How many credit hours will a student have to take for the two tuition costs to be equal? round the answer to the nearest tenth of an hour.

How to do this , and can some one explain

Use the quadratic formula to solve the equation. if necessary, round to the nearest hundredth. x^2 - 23 = 10x a. -1.93, 11.93 b. 1.93, -11.93 c. 1.93, 11.93 d. -1.93, -11.93