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Warmups. Find the slope. (2, -5) (3, 1) (-6, 4) (3, 7) Find the value of r. (5, r) (-2, 4) m = -1 (r, 5) (-2, r) m =. 6-2 Writing Linear Equations in Point-Slope and Standard Forms. Objective: To write a linear equation in point-slope form. Point-Slope Form. y – y 1 = m(x – x 1 )
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Warmups Find the slope. • (2, -5) (3, 1) • (-6, 4) (3, 7) Find the value of r. • (5, r) (-2, 4) m = -1 • (r, 5) (-2, r) m =
6-2 Writing Linear Equations in Point-Slope and Standard Forms Objective: To write a linear equation in point-slope form
Point-Slope Form y – y1 = m(x – x1) (x1 ,y1)m = rise = slope pointrun
Writing in Point-Slope • Given a point and a slope, write an equation in point-slope form y – y1 = m(x – x1) Example 1: (3,8) m = 2 y – 8 = 2 (x – 3) x1, y1
Example 2 y – y1 = m(x – x1) (-6,1) m = -4 (5,-2) m= y – 1 = -4(x + 6) x1, y1 Opposite sign than ordered pair!
Examples 3 & 4 4. (-1,6) m = undefined (no) x = -1 y – y1 = m(x – x1) 3. (2,5) m = 0 y – 5 = 0(x – 2) y – 5 = 0 y = 5
Example 5 Given 2 ordered pairs, write an equation in point-slope form: (6,3) (-8,5) Steps: • Find slope m = y2 – y1 x2 – x1 • Pick an ordered pair There are 2 possible answers! m = 5 – 3 -8 – 6 y – 3 = -1/7(x – 6) or y – 5 = -1/7(x + 8) = 2 -14 = -1 7
Example 6-7 Given 2 ordered pairs, write an equation in point-slope form: (-1,-7) (1,3) (-4,6) (-2,5)
TOO Given 2 ordered pairs, write an equation in point-slope form: (2,-6) (2,5) (5,3) (-2,3)
Homework • Pg. 336 #18-26, 33-38