Finding Slope and Writing Equations in Slope-intercept Form
Standard: A.CED.2(Algebra. Creating Equations.)
Essential Questions
• How do I find slope using the slope formula?• How do I rewrite an equation in slope-
intercept form?• How do I identify the slope and the y-
intercept?
Finding Slope
12
12
xx
yy
M =
Example 1:
Find the slope using the following points:
A line contains the points (–1, 3) and (2, –3).
Find m. m =–3 – 3
2 – (–1)
–6
3= –2=
Example 2:
Find the slope: (-4, -2) and (2, -2)
The slope of a horizontal line is ZERO!
Example 3:
Find the slope: (1, 4) and (1, -3)
The slopes of vertical lines are UNDEFINED!
Example 4:
Find the slope: (4, -2) and (-2, 6)
Example 5: Signs of slope
Positive, negative, zero, or undefined:
QUICKLY:
Textbook pg. 25, #’s 1-3 all, 14-26 EVEN
Pg. 25, #’s 1-3, 14-26 EVEN
1. Positive2. Negative3. Undefined14. -4/516. -3/518. Undefined20. ½22. -1/4
24. 126. 1
Writing Equations and Identifying “m” and “b”
y = mx + bm = slopeb = y-intercept**If an equation is not in slope-intercept form,
just get “y” by itself. Then, identify the “m” and the “b”.
Example 1
• Write an equation for the given information in slope-intercept form:
• M = 2, b = 3• Y = 2x + 3• M = -3, b = -4• Y = -3x – 4• M = ½, b = -5• Y = ½ x - 5
Example 2:
• Write the equation in slope-intercept form, then identify the m and the b:
• -2x + 3y = 9
Example 3
• Write the equation in slope-intercept form, then identify the m and the b:
• 4x + y = 3
Example 4:
• Write the equation in slope-intercept form, then identify the m and the b:
• 5x – 4y = 12
Example 5:
• Write the equation in slope-intercept form, then identify the m and the b:
• 2x – y = 3
QUICK!
Textbook pg. 32, #’s 2-12 EVEN and #14 and #15
Pg. 32, 2-12 EVEN, 14-15
2. 3/2; 14. 5; -46. -9; 88. 3; -110. 3; 1/312. ¼; 5/814. 0; -415. undefined; none
Homework:
• Workbook pg. 25-27, #’s 1-30 ALL• Workbook pg. 32 #’s 1-12 ALL
• SHORT GRAPHING AND INTERCEPT QUIZ THE NEXT TIME YOU COME IN HERE!!!
Pg. 25-27
1. Neg2. Undefined3. Pos4. Zero5. Pos6. Neg7. Pos8. Zero9. Neg10. Pos
11. Undefined12. Neg13. 114. -215. 016. -117. Undefined18. 219. 3/220. -1/2
Continued…
21. Undefined22. 123. -524. 325. -226. -627. 128. -2
29. 030. undefined
Pg. 32, #’s 1-12
1. 2; 12. 2/3; 13. -1/2; 24. 2; 25. ½; -16. 3/2; 17. 3; 48. 5; -29. -2; 8
10. ½; 011. -3/4; -112. 4; 4
