Write an equation that gives the proportional relationship of the graph. A) y = 1 8 x B) y = 8x C) y = 9x D) y = 72x

For this case we must find a function of the form:
 [tex]y = mx + b [/tex]
 Where,
 m: slope of the line
 b: cutting point with the y axis.
 We note that the cutoff point with the y axis occurs at 0.
 Therefore we have:
 [tex] b = 0 [/tex]
 On the other hand, the slope of the line is given by:
 [tex]m = \frac{y2-y1}{x2-x1} [/tex]
 Substituting values we have:
 [tex]m = \frac{72-0}{9-0} [/tex]
 Rewriting:
 [tex]m = \frac{72}{9} [/tex]
 [tex]m = 8 [/tex]
 Then, replacing values the equation of the line is:
 [tex]y=8x[/tex]
 Answer:
 [tex]y=8x[/tex]
 B) y = 8x