Monday, 2/8/10 SWBAT…Write and graph eqns in slope-intercept form Agenda 1. WU (10 min) 2. Review hw#5 (25 min) 3. Quiz (15 min) Warm Up: Q1-2: Write an equation of the line that passes through each pair of points 1.(6, -3), (12, -3)2. (9, -4), (3, -6) 3.Write an equation of the line that has an x- intercept of -2 and a y-intercept of 4. HW: Review past notes & re-do in class problems!
Back of agenda practice problems ANSWERS #5.) y = 6x – 22 #6.) y = -2x + 5
4 th period: Monday, 2/8/10 SWBAT…Write and graph eqns w/ parallel (║) and perpendicular(┴) lines Agenda 1. WU (5 min) 2. Review hw#5 (20 min) 3. Brain Pop Video (5 min) 4. Graphing parallel and perpendicular lines – (10 min) 5. Examples (10 min) Warm Up: Q1-2: Write an equation of the line that passes through each pair of points 1.(6, -3), (12, -3)2. (9, -4), (3, -6) 3.Write an equation of the line that has an x- intercept of -2 and a y-intercept of 4. HW#6: Parallel and perpendicular lines
Topic = Writing equations with PARALLEL lines
Graph the below equations on the same coordinate plane: 1.) y = -2/3x + 2 m = ___ 2.) y = -2/3x – 3 m = ___ What can you conclude about parallel lines and their slope?
Ex 1-2 directions: Find the slope of a line parallel to each line given: Ex 1. y = 3x + 2 Answer: m = 3 Ex 2. y = – 4 Answer: m =
Ex 3 directions: Write the equation of a line that is parallel to the line y = ½x – 7 and passes through the point (4, -2). Step 1: Find the slope: The line parallel to y = ½x – 7 has the same slope, ½. So, m = 1/2
Replace m with ½ and (x, y) with (4, -2) in the slope-intercept form Step 2: Substitute the values for x and y to find b y = mx + b -2 = (1/2)(4) + b -2 = 2 + b (Subtract 2 from both sides) -4 = b Step 3: Write the equation y = mx + b y = ½x + (-4) OR y = ½x – 4
Topic = Writing equations with PERPENDICULAR lines
Graph the below equations on the same coordinate plane: 1.) y = -4x + 2 m = ___ 2.) y = 1/4x – 3 m = ___ What can you conclude about perpendicular lines and their slope?
Ex 4-5 directions: Find the slope of a line perpendicular to each line given: Ex 4. y = 3x + 2 Answer: m = -1/3 Ex 5. y = – 4 Answer: m = -2
Ex 6 directions: Write the equation of a line that is perpendicular to the line y = -½x and passes through the point (-2, 0). Step 1: Find the slope: The line perpendicular to y = -½x has the opposite reciprocal slope, 2. So, m = 2 HW Prob #12
Replace m with 2 and (x, y) with (-2, 0) in the slope-intercept form Step 2: Substitute the values for x and y to find b y = mx + b 0 = (2)(-2) + b 0 = -4 + b (Add 4 to both sides) 4 = b Step 3: Write the equation y = mx + b y = 2x + 4
Write the equation of the line parallel to the line 4x – 5y = 7 that passes through the point (-3, 7). y – y 1 = m(x – x 1 )
Write the equation of the line perpendicular to the line 3x + 2y = 9 that passes through the point (2, 5). y – y 1 = m(x – x 1 )