Question 290413
This is just a fancier way of asking for an equation of a line through two points.
(1,12)
(-2,-3)
They you you to call it g(x) instead of y
(y-y)/(x-x)=m
after you have found m then you need to find b
y=mx+b
substitute m,(either  x and y ) and find b
When you are done call it g(x)=mx+b inserting your new values of m and b