SWBAT Write lines in slopeintercept form Wed 22010

SWBAT… Write lines in slope-intercept form Wed, 2/20/10 Agenda 1. Warm-up (10 min) 2. Notes on slope intercept – 4 examples (30 min) 3. Exit slip (5 min) WARM-UP http: //nlvm. usu. edu/en/nav/frames_asid_33 2_g_4_t_2. html? from=category_g_4_t_2. ht ml HW#3: Writing equations in slope-intercept form

Slope-intercept form: Now look at the equation below…… What is the slope? ______ What is the y-intercept? ______

Given y = ½x + ¾, what is the slope and the y-intercept? m=½ b=¾

Given y = ½x – ¾, what is the slope and the y-intercept? m=½ b = -¾

Given y = -½x – ¾, what is the slope and the y-intercept? m = -½ b = -¾

• y = mx+ b is an equation that defines a line • A line has two characteristics 1. Slope 2. Points that fall on the line

Converting linear equations into Slope. Intercept Form 4 Examples

Slope intercept form is: y = mx + b Our main goal is to get the y alone on one side of the equation

Example 1 - convert into slope-intercept form 2 1 (divide both sides by 2 to get y alone) (now simplify all fractions) Slope (m) = 2 y-intercept (b) = 1

*** Your turn – Example 2 – convert into slope-intercept form *** 5 y = 10 x + 15 5 2 3 y = 2 x + 3 Slope (m) = 2 y-intercept (b) = 3 (divide both sides by 5 to get y alone) (now simplify all fractions) BRAVO!!

*** Your turn – Example 3 – convert into slope-intercept form *** -3 y = -9 x – 12 Step 1: divide both sides by -3 to get y alone Step 2: Simplify all fractions Step 3: Write your equation in y = mx + b Slope (m) = y-intercept (b) =

*** Check Your Answer *** -3 y = -9 x – 12 -3 -3 -3 (divide both sides by -3 to get y alone) (now simplify all fractions) y = 3 x + 4 Slope (m) = 3 y-intercept (b) = 4

Example 4 - convert into slope-intercept form 21 x – 7 y = 14 -21 x (subtract both sides by 21 x) -7 y = -21 x + 14 (divide both sides by -7) -7 -7 -7(simplify all fractions) y = 3 x – 2 3 Slope (m) = 3 y-intercept (b) = -2 2

***EXIT SLIP *** 2 y + 26 = -6 x Step 1: Subtract both sides by 26 Step 2: Divide both sides by 2 to get y by itself Step 3: Simplify all fractions Slope (m) = y-intercept (b) =

*** Check Your Answer *** 2 y + 26 = -6 x (subtract both sides by 26) (now divide both sides by 2 2 y = -6 x – 26 (simplify all fractions) y = -3 x – 13 Slope (m) = -3 y-intercept (b) = -13