1. Wed, 2/10/10 SWBAT…Write and graph eqns in standard form and point-slope form
Agenda
WU (10 min)
Cornell notes / 7 Examples
Warm Up: Simplify each expression
-1(-3x + y)
-2( y)
3. -5(x + 3)
HW#7-standard form and HW#8-point-slope form 1

2. Writing Equations of Lines
Standard Form

3. Ax + By = C A and B are not both zero A ≥ 0
STANDARD FORM
The STANDARD FORM of an equation of a line is
Ax + By = C
A and B are not both zero
A ≥ 0
A , B, and C are integers (not fractions)

4. Convert y = 8 – 2x to standard form.
HW Prob #1
EXAMPLE 1
Convert y = 8 – 2x to standard form.

5. Convert y = 3x + 12 to standard form.
HW Prob #3
EXAMPLE 2
Convert y = 3x + 12 to standard form.
multiply both sides by -1

6. Convert y = 6776x to standard form.
HW Prob #6
EXAMPLE 3
Convert y = 6776x to standard form.
multiply both sides by -2

7. Convert y = 6776x to standard form.
ADDITIONAL EXAMPLE 4
Convert y = 6776x to standard form.
multiply both sides by -4

8. Writing Equations of Lines
Point-Slope Form

9. y – y1 = m(x – x1) m is the slope (x1, y1) is a point on the line
Point-Slope Form
y – y1 = m(x – x1)
m is the slope
(x1, y1) is a point on the line

10. HW Prob #1
EXAMPLE 1
Write the equation of the line in point-slope form with slope 3 that passes through (1, 5).
(x1, y1)
y – y1 = m(x – x1)

11. HW Prob #3
EXAMPLE 2
Write the equation of the line in point-slope form with slope ¾ that passes through (-4, 3).
y – y1 = m(x – x1)

12. Write the equation of the line in standard form.
HW Prob #4
EXAMPLE 3
Write the equation of the line in standard form.

13. Write the equation of the line in slope-intercept form.
HW Prob #8
EXAMPLE 4
Write the equation of the line in slope-intercept form.

14. ADDITIONAL EXAMPLE 5
Write the equation of the line in point-slope form with slope 3 passing through point (1, 5).
(x1, y1)
Use Point-Slope Form
y – y1 = m(x – x1)

15. ADDITIONAL EXAMPLE 6
Write the equation of the line with slope ¾ and passing through the point (-5, 3).
Use Point-Slope Form
y – y1 = m(x – x1)

16. Why does the point-slope form work?
Find the slope between (x1, y1) and (x, y).
Reflexive
propetry
Point-Slope Form