### Chapter 1, “Points and Lines”

#### Equation of a Line

The graph of an equation of the form Ax + By = C, where A and B are not both 0, is a straight line.

#### Slope

For any line in standard form, Ax + By = C, the slope m = –A/B.

#### Parallel Lines

If two lines are parallel, their slopes must be equal.

#### Perpendicular Lines

If two lines are perpendicular,

#### Equation of a Line

Slope-intercept form: y = mx + b

Point-slope form: (y – y_{1}) = m(x – x_{1})

where (x_{1},y_{1}) is a point on the line.

#### System of Linear Equations

A system of two linear equations in the same plane has ...