Explain how to find the Great Common Factor.

Ineed if you could explain and give me the answer you! this needs done

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.

Ineed with number 6 , explain how to get 1978