step 1
Find the equation of function A
Find the slope
take the points
(1,7) and (3,11)
m=(11-7)/(3-1)
m=4/2
m=2
Find the equation in point slope form
y-y1=m(x-x1)
we have
m=2
(x1,y1)=(1,7)
substitute
y-7=2(x-1)
Find the y-intercept
REmember that te form
y-y1=m(x-x