The gradient of a straight line describes the slope or steepness of the line. \(\text{Gradient =}~\frac{change~in~y}{change~in~x}\) To determine the gradient of a line: choose any two points on ...

Then, type the formula below in the formula ... Since the trend line is a straight y = ax + b line, you can calculate the slope (a) yourself. But this is Excel, so let Excel do the calculations.