3/5y+(-6/5y) help me plz

How do you answer this question? (step by step)

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.

How much orange juice do you need to make 2 servings of lemony orange slush?