Equation of a Straight Line. The equation of a straight line is usually written this way: y = mx + b. (or 'y = mx + c' in the UK see below) . Every straight line can be represented by an equation: y = mx + b. The coordinates of every point on the line will solve the equation if you substitute them in the . Ever need to know the slope of your driveway? Sub some into y=mx+b. Ever need to know at what angle your ladder is standing at if it was on a graph? y=mx+b A linear function is of the form y = mx + b. In the applet below, move the sliders on the right to change the values of coefficients m and b and note the effects it has . Covers the 'slope-intercept', or 'y = mx + b', form of straight-line equations. y=mx+b: slope discovery. . y=mx+b: slope discovery. Create AccountorSign In. y = m x + b. 1. b =1. «1x». 7391−10. 739110. 2. m =1. «1x». 7391−10. 739110. 3. 1,1. Label. points on the graph of y = mx + b. Then y1. = mx1. + b and y2. = mx2. + b. Use algebra to simplify y2 – y1 x2 – x1. And give a geometric interpretation. Try this!