# Basic Algebra

### Topics

## Introduction to :

Another way to graph a line is to get it in slope-intercept form: *y = mx + b*, where

*m*is the**slope**of the line*b*is the**y-intercept**

Since we are given a point of the line, and the slope, we can find an infinite number of other points on the line and connect them.

*Remember: slope (m) is equal to the (change in y) / (change in x). Slope = "rise over run"*

## Slope-intercept form of a line: *y = mx + b*

Let's examine how to graph one of these equations: y = 2x + 1.

This is in slope-intercept form, so we know that the number in front of x is the slope (2), and that 1 is the y-intercept.

Start by plotting the y-intercept.

Next, since we know that the slope is , also known as , we know that another point will be two spaces up and one over (in the positive direction of course).

Finally, connect these points.

**Look Out:** when using slope-intercept form to graph lines, you must solve the equation for y, not x.

#### Example 1

Graph the equation y = -½x – 2. |

#### Example 2

Graph the equation 4x + y = 7. |

#### Example 3

Graph the equation 2y = x. |

#### Example 4

Find the equation of the line in slope-intercept form. |