# Slope-intercept form review

CCSS Math: 8.F.A.1, 8.F.A.3, 8.F.B.4, HSF.LE.A.2

Review slope-intercept form and how to use it to solve problems.

## What is slope-intercept form?

Slope-intercept is a specific form of linear equations in two variables:

When an equation is written in this form, $\maroonC m$ gives the slope of the line and $\greenD b$ gives its $y$-intercept.

*Want to learn more about slope-intercept form? Check out this video.*

## Finding slope-intercept equation from features or graph

### Example 1: Equation from slope and intercept

Suppose we want to find the equation of the line whose slope is $\maroonC{-1}$ and $y$-intercept is $(0,\greenD5)$. Well, we simply plug $\maroonC{m=-1}$ and $\greenD{b=5}$ into slope-intercept form!

### Example 2: Equation from two points

Suppose we want to find the line that passes through the points $(0,-4)$ and $(3,-1)$. First, we notice that $(0,\greenD{-4})$ is the $y$-intercept. Second, we use the two points to find the slope:

Now we can write the equation in slope-intercept:

*Want to try more problems like this? Check out these exercises:*

## Finding features and graph from slope-intercept equation

When we have a linear equation in slope-intercept form, we can quickly find the slope and $y$-intercept of the corresponding line. This also allows us to graph it.

Consider, for example, the equation $y=\maroonC2x\greenD{+3}$. We can quickly tell that the corresponding line has a slope of $\maroonC2$ and its $y$-intercept is $(0,\greenD{3})$. Now we can graph the line:

*Want to try more problems like this? Check out these exercises:*