 So we're going to jump straight in with you trying a question yourself. If you aren't sure, watch part one first. Find the equation of the line that passes through the points 2, 10 and 5, 1. Pause the video, work out the answer and click play when you're ready to jump. Did you get y equals negative 3x plus 16? If you got it right and you want to skip the explanation, click here. Otherwise, keep watching. So we start by finding the gradient. I'm going to use that really easy little equation with 2, 10 as my ones and 5, 1 as my twos. So we get 1 minus 10 divided by 5 minus 2, which gives us negative 9 divided by 3. So our gradient is negative 3. Now using the y equals mx plus c format with the gradient m as negative 3, we have y equals negative 3x plus c. So to find the missing y intercept, the c, we just substitute in either 2, 10 or 5, 1. It doesn't matter, just choose one of them. I'm going to use 5, 1, so when x is 5, y is 1. So 1 equals negative 3 multiplied by 5 plus c. So 1 equals negative 15 plus c, a little bit of rearranging, add 15 to both sides, c equals 16. So the gradient m was negative 3 and the y intercept c is 16, which means the equation of the line is y equals negative 3x plus 16. So that is all there is for finding the equation of a straight line through 2 points. We use the y equals mx plus c equation and for the gradient m, we've got that really easy little equation. And then to find the y intercept, you just use a set of coordinates from the question. And that's how you find the equation of a straight line through 2 points.