How to Estimate the Y Intercept in Excel. When you graph a series of (x,y) coordinates in Microsoft Excel 2010, you can use the program's built-in functions to display the equation for the line ...

One line, 𝒚 = 3 - 4𝒙, has a negative gradient. Each positive gradient is multiplied by the negative gradient to find if any product is -1. ¼ × -4 = -1.

The y-intercept is the point at which a linear equation crosses the y-axis on the x=0 plot point. The equation to determine both the slope and the y-intercept of a line is y=mx+b.