We first get the gradient of the equation of a line by taking the change in y over change in x
Hence our gradient will be
(6-9.5)/(8-1)=-3.5/7=0.5
Taking an arbitrary point(x,y) and using our gradient we get and one of the points above we get
(y-6)/(x-8)=0.5
y-6=0.5*(x-8)
y-6=0.5x-4
y=0.5x+2 or y=1/2x+2
which is the line of our equation the answer we are asked for.