The slope-intercept is y=mx+b where m= the slope and b= the y-intercept. it looks like the y-intercept is about 3.5 or 3 1/2. One way to find M is that you take 2 points, ill do (1,5) and (5,12), and then subtract the x's with the x's and the y's with the y's and you would get (1-5, 5-12) which equals -4,-7. then you put the y's on top of a fraction and the x's on the bottom. so you would get -7/-4 when both numerator and denominator are both negative then they cancel out. making the total M= 7/4 which also equals 1 and 3/4, since you want to know after 13 months, the number of months =x so you can substitute and this is your equation: y= 7/4x+ 3.5 substituting the number of months: y= 7/4(13) + 3.5. 7/4 * 13 = 22.75 then you add the 3.5 which equals 26.25 so.
after 13 months of practice, the number of matches won would be about 26.