Find the average rate of change in the simplest form of the function over the interval​

x = 9.5

this should be the right answer if the same one you had to solve.

Step-by-step explanation:

y = 2x - 4

y = 12 + 3                             combine them

2x - 4 = 12 + 3

    +4         +4                   The 4's cancel each other out

2x = 12 + 7                     Add then divide

 2x = 19

  2x = 19

   19   19

 x = 9.5