Point-slope Form - Equations of straight lines

If you'd like to use an online calculator for straight lines, go to: http://matrixlab-examples.com/equation-of-a-straight-line.html

I'm gonna show you how to express the point-slope form for straight lines.

If you know that the slope of a line is m and also know any point (x1, y1)

Then, the point-slope equation of that line is y - y1 = m (x -- x1) In this example, if we have a slope of -3 and the point (1, 1) then, our point-slope equation is y minus 1 equals -3 times x minus 1 y - 1 = -3 (x -- 1)

In this other example, if we have points (0, 5), (-2, 1) we can calculate the slope and discover that it's 2. m = (5 - 1) / (0 + 2) = 2

Using one point we get the equation: y - 5 = 2x and using ghe other point we get another expression of the same line: y - 1 = 2(x + 2)

In this last example we have two point that allow us to calculate the slope: m = 6/2 = 3

and use the two given points to find our needed equation Point-slope form 1: y - 7 = 3x Point-slope form 2: y - 1 = 3(x + 2)

Thank you for watching!