Wed, 2/10/10 SWBAT

1
Wed, 2/10/10SWBATWrite 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)
• HW7-standard form and HW8-point-slope form

2
STANDARD FORM
The STANDARD FORM of an equation of a line is Ax
By C

• A 0
• A and B are not both zero
• A , B, and C are integers (not fractions)

3
Convert y 8 2x to standard form.
HW Prob 1
4
Convert y 3x 12 to standard form.
multiply both sides by -1
5
Convert y 6776x to standard form.
multiply both sides by -2
6
Point-Slope Form
Writing Equations of Lines

• Ms. Sophia Papaefthimiou
• Infinity High School

7
Point-Slope Form
y y1 m(x x1) m is the slope (x1, y1) is
a point on the line
8
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)
9
Write the equation of the line in point-slope
form with slope ¾ that passes through (-5, 3)
(x1, y1)
y y1 m(x x1)
10
Write the equation of the line in slope-intercept
form
y y1 m(x x1)
11
Write the equation of the line, in point-slope
form, passing through the points (4, 3) and (6,
8).
y y1 m(x x1)
Find the slope
let's use (4, 3)
12
In point-slope form, write the equation of the
line passing through the points (-2, 6) and (3,
-1).
y y1 m(x x1)
Find the slope
let's use (-2, 6)
13
In point-slope form, write the equation of the
line passing through the points (-2, 6) and (3,
-1).
y y1 m(x x1)
Find the slope
let's use (3, -1)
14
Graph y 2 2(x 3) (HW Prob 8)
Graph the line using the points and slope
Find the slope
y
Find the x and y coordinates
x
15
Graph y 5 3(x 2)
Graph the line using the points and slope
Find the slope
y
Find the x and y coordinates
x
16
Graph y 1 (x 1)(HW Prob 9)
Graph the line using the points and slope
Find the slope
y
Find the x and y coordinates
x
17
Why does the point-slope form work?
Find the slope between (x1, y1) and (x, y).
Reflexive propetry
Point-Slope Form