# Slope-intercept form review

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

## 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!
$y=\maroonC{-1}x\greenD{+5}$

### 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:
$y=\maroonC{1}x\greenD{-4}$
Problem 1
Write the equation of the line whose slope is $5$ and $y$-intercept is $(0,-7)$.
$y=$

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:
Problem 1
What is the slope of the line $y=3x-1$?
What is the $y$-intercept of the line?
$(0,$
$)$

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