Using f(x) = y, we know that a graph of the function contains the (x,y) points (2,5) and (6,-1). first find the slope of that line, m = (y2 - y1)/(x2 - x1) ⇒ -6/4⇒-3/2
then using either point (I'll use the first one) solve for b in y = mx + b. 5 = (-3/2)(2) + b⇒ 5 = -3 + b⇒ 8 = b.
