Since R is the midmoint of QS that means that QR and RS are equal to each other. So first you need to find x. There are many different ways to set up the equation to solve for x, but I'll show you the easiest one:
Y= 2x+6 You just have to go back wards from what you have. You already know the slope is 2 and slope is the change is y over the change in x. 2=2/1 So every time you take away 1 from x, you’re going to take away 2 from y. (2,10) will become (1,8) which will be come (0,6). You know have your y intercept (6) So the equation for the line is y=2x+6