Find the lenght of DF. Figure is not drawn to scale. ​

What is the missing step in this proof ?

Need ! the total ticket sales for a high school basketball game were $2,260. the ticket price for students were $2.25 less than the adult ticket price. the number of adult tickets sold was 230, and the number of student tickets sold was 180. what was the price of an adult ticket?

Common binomial factor of 6x(3x+7)+5(3x+7)