The graph of an equation of the form Ax + By = C, where A and B are not both 0, is a straight line.
For any line in standard form, Ax + By = C, the slope m = –A/B.
If two lines are parallel, their slopes must be equal.
If two lines are perpendicular,
Slope-intercept form: y = mx + b
Point-slope form: (y – y1) = m(x – x1)
where (x1,y1) is a point on the line.
A system of two linear equations in the same plane has ...