Pick any two points to find the slope using the change in y (Y2 - Y1) divided by the change in x (X2 - X1). For example, if we use points (-2, 4) and (-1,2), we have (4-2)/([-2]-[-1])=2/(-1)=-1 so m=-2. Use point slope form and one of the points to get the equation: y-(2)=-2(x-[-1]) which becomes y= -2x when we solve for y. Here, you want to check if the 3rd point is on the line, otherwise it's not possible to make a line. plug in x=-4, and we get y=-2(-4)=8, which is perfect.
Dec 9th, 2014
Are you studying on the go? Check out our FREE app and post questions on the fly!