2 times as many as 8 is 16

The table respent two linear functions the equation respented by the first tables is given

Tod does not have any cookies. david gives jeff 8 cookies. then he splits half of the cookies he has left with tod. david let’s c represent the number of cookies that he starts with. he finds the number of cookies that tod has is 1/2 the difference of c and 8. write an expression to represent the number of cookies that tod has.

Complete the solution of the equation. find the value of y when x equals to 28 x+3y=28