This produces very nice complex graphs. There are multiple equations in the drop-down list then scroll down and select one of them to meet your actual needs. That equation includes a slope and intercept value.
The following window will appear on the screen in which click on the Insert New Equation option.
Equation of a line. In the Professional format. On the Insert tab in the Symbols group click the arrow next to Equation and then click Insert New Equation On the Insert tab in the Symbols group click the Equation button Or simply press Alt. Go to Insert tab find Symbols group and click Equation button.