How does one find the equation of a line passing through 2 points of a graph?
The general equation for a line on a graph is: y = mx + b ,where a is called the slope of the graph and b is the y-intercept(or the point where the line crosses the y axis). Let's assume the 2 points have the following coordinates (x1 , y1) and (x2 , y2). Subtracting the 2 equations from one another to get, y1 -y2 = mx1 + b - mx2 -b . The b's could be cancelled out and the m is a common multiplier , which means the equation could be written as:y1-y2 = m(x1-x2) or m = (y1-y2)/(x1-x2). Assuming we know all x's and y's m could be calculated. The final step of finding b could be done by substituting m and a pair of x and y into the first equation(y=mx+b)
