Respuesta :

Using your approximate y-intercept on the line of best fit, your equation would be y=11/7x + 3. 

We find the slope by choosing two points that are on the line:

(9, 18) is easy to spot; and (2, 7) is fairly easy to spot as well.  The formula for slope is:
m=y₂-y₁/x₂-x₁

m=7-18/2-9 = -11/-7 = 11/7

Slope intercept form, y=mx+b, has the slope and the y-intercept.  Plugging those in we have y=11/7x+3.
The generic equation of the line is:
 y-yo = m (x-xo)
 We look for the slope:
 m = (y2-y1) / (x2-x1)
 m = (18-15) / (9-7)
 m = (3) / (2)
 m = 3/2
 We write the equation choosing any point:
 y-15 = (3/2) (x-7)
 we rewrite the equation:
 y-15 = (3/2) x-10.5
 y = (3/2) x-10.5 + 15
 y = (3/2) x + 4.5
 Then, for x = 13 we have:
 y = (3/2) * (13) +4.5
 y = 24
 Answer: 
 The equation is:
 y = (3/2) x + 4.5
 
The number of matches won for 13 months is:
 y = 24