Answer: D
Step-by-step explanation: Notice that if you multiply both sides of the equation of y2 = m (x2 - x1) + y1 by X2 - X1.
This gives you m(X2 - X1) = Y2 - Y1.
Then add Y1 to both sides to get m(X2 - X1) + Y1 = Y2.
This slope would be equivalent to the usual slope formula.
