1. Quick Graphs Using Slope-Intercept Form
Algebra 1 Section 4.6
Quick Graphs Using Slope-Intercept Form

2. Important!!!
This is a big concept in Algebra 1. You need to thoroughly understand this!
Slope – Intercept Form
y = mx + b
m represents the slope
b represents the y-intercept

3. Writing Equations
When asked to write an equation, you need to know two things – slope (m) and y-intercept (b).

4. Example 1: Writing Equations
Write an equation in slope-intercept form of the line that has a slope of 2 and a y-intercept of 6.
To write an equation, you need two things:
slope (m) =
y – intercept (b) =
We have both!! Plug them into slope-intercept form
y = mx + b
y = 2x + 6 2 6

5. Writing Equations
Write an equation in slope-intercept form for the following:

6. y = -3x – 4 y = -4x – 3 y = -3x + 4 y = -4x + 3
Write the equation of a line that has a y-intercept of -3 and a slope of -4.
y = -3x – 4
y = -4x – 3
y = -3x + 4
y = -4x + 3

7. To find the slope and y-intercept of an equation, write the equation in slope-intercept form: y = mx + b.
Find the slope and y-intercept.
y = 3x – 7
y = mx + b
m = 3, b = -7

8. Find the slope and y-intercept.
2) y = x
y = mx + b
y = x + 0
3) y = 5
y = 0x + 5
m =
b = 0
m = 0
b = 5

9. Find the slope and y-intercept. 4) 5x - 3y = 6
m =
b = -2

10. Find the slope and y-intercept. 5) 2y + 2 = 4x
Write it in slope-intercept form.
(y = mx + b)
2y + 2 = 4x
2y = 4x – 2
y = 2x - 1
m = 2
b = -1

11. Find the slope and y-intercept of y = -2x + 4
m = 2; b = 4
m = 4; b = 2
m = -2; b = 4
m = 4; b = -2

12. Example 2: Graphing Using Slope and y-Intercept
When given an equation, you can easily graph it in slope-intercept form. All you need is two things– the slope (m) and y-intercept (b).

13. Graphing Using Slope and y-intercept
Step 1: Make sure the equation is in slope-intercept form
Step 2: Find the slope and y- intercept
Step 3: Plot the y-intercept
Step 4: Apply the slope (rise/run) to the y-intercept

14. Review: Graphing with slope-intercept-3 1 -3
Start by graphing the y-intercept (b = 2).
From the y-intercept, apply “rise over run” using your slope. rise = 1, run = -3
Repeat this again from your new point.
Draw a line through your points. 1
Start here

15. Graph: Step 1: y=mx+b Step 2: slope = 2 y-intercept = 3
Step 3: plot the y-intercept on a graph
Step 4: apply the slope

17. Graph the following equations:

18. Homework: Complete Study Guide for Chapter 4  due Tuesday, November 19th