Question 698594
The question is not clear. 
Given two points (x1,y1) and (x2,y2) you can find the slope by plugging in these values into the formula you mentioned, M= y2-y1/x2-x1     where m is the slope. Another way you find the slope if you're given a linear equation ax+by=c you would solve for y and put the equation into slope intercept form which would y=mx+b where m is the slope.