Question

Please help!
Given the chart below:

x -6 -1 3 5 8 13
g(x) 22 7 -5 -11 -20 -35

answer each of the following

a.) find a formula for this set of data

b.) what is the value of g(-21)?

c.) find the value of k such that g(k)=k-12

Answer 1

for a I don't know if I'm doing it right. I found the slope to be -3 because
m=(22-7)/(-6+1)
m=15/-5
m=-3

Answer 2

now I think I do y-y1=m(x-x1)? not really sure