Find the Equation Using Two Points (-10,-20) , (1,-9)

Use ${\displaystyle y=mx+b}$ to calculate the equation of the line, where ${\displaystyle m}$ represents the slope and ${\displaystyle b}$ represents the y-intercept.

Slope is equal to the change in ${\displaystyle y}$ over the change in ${\displaystyle x}$, or rise over run.

The change in ${\displaystyle x}$ is equal to the difference in x-coordinates (also called run), and the change in ${\displaystyle y}$ is equal to the difference in y-coordinates (also called rise).

Substitute in the values of ${\displaystyle x}$ and ${\displaystyle y}$ into the equation to find the slope.

Now that the values of ${\displaystyle m}$ (slope) and ${\displaystyle b}$ (y-intercept) are known, substitute them into ${\displaystyle y=mx+b}$ to find the equation of the line.