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Writing equations given m and b or m and a point Slope-Intercept Form: y = mx + b To write an equation in Slope-Intercept Form, you must know m and b. Write an equation in Slope-Intercept Form. 1) m = -¼ and b = -7 2) m = 1 and b = -14 y = -¼x – 7 y = x – 14 3) b = 3 and m = 4 y = 4x + 3 If you are given an ordered pair, you know x and y. 4) m = ⅔ and (0, -10) y = ⅔x – 10 Standard Form: 5) m = ⅜ and (-16, 7) y = ⅜x + 13 6) m = -1 and (4, -2) y = -x + 2 Ax + By = C where A, B, C are integers and A is positive Transform the equation into standard form. 7) y = -7x – 2 8) y = -½x + 11 7x + y = 2 x + 2y = 22 9) y = 3x + 9 3x – y = -9 Write an equation in standard form. 10) m = 5 and b = -16 11) 5x – y = 16 12) m = 1 and (-3, -5) x–y=2 Activity: m = -⅞ and (4, 0) 7x + 8y = 28 Wipe Boards S/I: m = 6 and b = -18 y = 6x – 18 STD: m = 7/2 and b = 12 7x – 2y = -24 S/I: m = -3/5 and (10, -1) y = -3/5x + 5 STD: m = -½ and (4, 7) x + 2y = 18 STD: m = 4 and (0, -3) 4x – y = 3 HOMEWORK: HW sheet Writing equations given two points To write an equation in slope-intercept form, you must know m and b. If you have two points, find m using the formula, then use it with one of the ordered pairs to find b. Write an equation in slope-intercept form. 1) (-6, -9) and (0, 5) 2) y = 7/3x + 5 3) (4, -5) and (2, -4) y = -½x – 3 (-2, -10) and (-5, -13) y=x–8 4) (5, -12) and (2, 0) y = -4x + 8 Write an equation in standard form. 5) (-4, 8) and (2, -7) 5x + 2y = -4 6) (9, 1) and (-3, -1) x – 6y = 3 7) 8) (11, 3) and (22, 6) 3x – 11y = 0 (-1, 8) and (2, -13) 7x + y = 1 Activity: Wipe Boards S/I: (4, 15) and (3, 11) y = 4x – 1 STD: (6, 22) and (-12, -20) 7x – 3y = -24 S/I: (4, -1) and (8, -7) y = -3/2x + 5 STD: (-7, 3) and (-2, 2) x + 5y = 8 STD: (3, 0) and (0, -6) 2x – y = 6 HOMEWORK: HW sheet 6-6 Writing equations given a variety of information 2 lines are parallel if they have the same slope. The symbol that represents parallel is ║ 2 lines are perpendicular if they have negative reciprocal slopes. The symbol that represents perpendicular is 1) What is the slope of the line parallel to a line whose slope is 6? 6 2) What is the slope of a line perpendicular to a line whose slope is –¾? 4/3 3) If one line has a slope of 3 and another line has a slope of ⅓ are they parallel, perpendicular or neither? neither Determine if the lines are parallel, perpendicular or neither. 4) y = -8x – 10 5) 4y = x + 12 y = ⅛x + 2 y = 4x + 1 perpendicular neither 6) 3x – 6y = -18 x – 2y = 14 parallel Write an equation in Slope-Intercept Form. State what you are given and what you will use. 7) ║ to y = 7x + 2 8) to x + 2y = -10 9) to 4y = 7x - 8 through (-1, 8) through (3, -20) through (28, -8) y = 7x + 15 y = 2x – 26 y = -7/4x + 41 Given Use m=7 m=7 X b = 15 Given m = -½ X Write an equation in Slope-Intercept Form. 10) x-int: 12 and y-int: -7 11) y = 7/12x – 7 Activity: Use m=2 Given Use m = 7/4 m = -4/7 b = -26 X x-int: -10 and y-int: 3 y = 3/10x + 3 Wipe Boards to y = 2/7x + 1 through (-2, 14) y = -7/2x + 7 ║ to x – 3y = 9 through (18, -2) y = ⅓x – 8 ║ to 5y = -3x + 5 through (15, -4) y = -3/5x + 5 x-int: -5 and y-int: -2 y = -2/5x – 2 HOMEWORK: HW sheet b = 41