How to find a slope in a graph

The chart below shows the distribution of weeds in yard

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).

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.