Learn how to calculate the equation of a line from a graph, work out the gradient from an equation, and visualise intercepts with this step-by step guide.

Each positive gradient is multiplied by the negative gradient to find if any product is -1. ¼ × -4 = -1. Therefore the lines 𝒚 = 𝒙/4 + 3 and 𝒚 = 3 - 4𝒙 are perpendicular.

The slope is a value that indicates the rate at which the y value of a line rises or falls as the x value increases. Using the SLOPE function in Excel, you can find this value for a set of ...