2.3 and 2.4 Handout

# 2.3 and 2.4 Handout - slope of 5 and a y-intercept of 7....

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Special Lines and Pairs of Lines and Writing Equations of Lines Sections 2.3 and 2.4 Horizontal Lines Vertical Lines Equation looks like: y = c Equation looks like: x = c Slope is: 0 Slope is: undefined Parallel Lines Perpendicular Lines Have equal slopes. Have negative reciprocal slopes. 4 x + 2 y = 8 b y = –2 x + 4 ( m = –2) 4 x + 2 y = 8 b y = –2 x + 4 ( m = –2) 2 x + y = 15 b y = –2 x + 15 ( m = –2) 3 x – 6 y = 12 b y = 1 2 x + 4 ( m = 1 2 ) These lines are parallel since their slopes These lines are perpendicular since their are equal. slopes are negative reciprocals. WRITING THE EQUATION OF LINES If you know the slope and the y -intercept If you don’t know the y -intercept (or can count them from a grid) y = mx + b y y 1 = m ( x x 1 ) and 2 1 2 1 y y m x x - = - What is the y -intercept? – plug this in for b Find m using the slope formula. What is the slope? – plug this in for m Then plug in y 1 , m , and x 1 into the equation and simplify. What is the equation of the line that has a Write the equation of the line that passes

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Unformatted text preview: slope of 5 and a y-intercept of 7. through (7, 3) and (5, 11). m = 5 and b = 7 so the equation is: Label! x 1 y 1 x 2 y 2 y = 5 x + 7 m = 11 3 8 4 5 7 2-= = ---y y 1 = m ( x x 1 ) y 3 = 4 ( x 7 ) y 3 = 4 x + 28 y = 4 x + 31 Quiz 3 Sections 2.3 and 2.4 MAT 1033 Name _____________________________ 1. For the line at the right: y = 2 Is it horizontal or vertical? What is the slope of the line? 2. Determine whether the two lines below are parallel, perpendicular, or neither. 3 6 6 2 10 x y x y-=- + = 3. Write the equation of the line shown in the graph below. [Hint count to find m and b .] 4. Write the equation of the line that passes through the points (1, 11) and (4, 2). ANSWERS: Horizontal m = 0 ANSWER: Parallel, both lines have a slope of one-half. ANSWER: 2 3 3 y x = + ANSWER: 3 14 y x = -+...
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## This note was uploaded on 10/01/2010 for the course MAT 1033 taught by Professor Berthiaume during the Fall '10 term at Edison State College.

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2.3 and 2.4 Handout - slope of 5 and a y-intercept of 7....

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