The first step in finding the slope of a line that is written in standard form is to write the equation in slope-intercept form, y=mx+b. To do this, rearrange the variables. The standard form, Ax + By = C can be rewritten as By = -Ax + C.
In the equation By = -Ax + C, B needs to be distributed through the equation. To do this, divide both sides by B. The answer is y = (-A/B)x + C/B.
Once the equation of the line is in slope-intercept form and is simplified, then the slope equals the term in front of the x variable. In the standard form from step 2, the slope is -A/B.