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WARM- UP!. 1.Write the equation in slope-intercept form 2x + y = 4 2.Write the x and y intercept of 2x + 3y = 6. OBJECTIVES:. Determining whether lines are parallel Writing equations of parallel lines 2/ 17/11. PARALLEL LINES.
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WARM- UP! • 1.Write the equation in slope-intercept form • 2x + y = 4 • 2.Write the x and y intercept of 2x + 3y = 6
OBJECTIVES: Determining whether lines are parallel Writing equations of parallel lines 2/ 17/11
PARALLEL LINES • Lines in the same place that never intersect are called parallel lines • Two lines are parallel if they have the same slope. • Use Slope-intercept form • y = mx + b
Ex. Are the graphs of these 2 lines parallel? • 3y = 2x + 15 Solution: Write the two equations in slope- intercept form • 3y = 2x + 15 3 3 y = ⅔ x + 5 The two lines are parallel • 2x – 3y = 3 • 2x – 3y = 3 -2x -2x - 3y = -2x +3 -3 -3 y = ⅔ x - 1
Example #2 Are the graphs of these 2 lines parallel? • x + 2y = 7 Solution: Write the two equations in slope- intercept form • -2x + y = 3
EQUTIONS OF PARALLEL LINES • Two lines are parallel if they have the same slope. • Example #1. Write the equation of a line that passes through ( -1, 3) and is parallel to 5x + y = 2 Step 1. Find the slope of the other line. Write the equation in slope-intercept form y = mx + b 5 x + y = 2 -5x -5x the two lines are parallel y = -5x + 2 so they have the same slope, m = -5
Step 2: Solve for b y = mx + b 3 = -5( -1) + b 3 = 5 + b -5 = -5 -2 = b • Step 3: Plug-in the values of m and b y = mx + b y = -5x – 2
WORK TIME:#1. Find the slope of a line parallel to the graph of 5x + y = 7.
#2.Write an equation for the line that is parallel to y = 2x + 6 and passes through (–1, 5).
#4. Find the slope of a line parallel to the graph of 4x – y = 8.
WORK TIME: 15 MINUTES ONLY! Nothing will work unless you do.
SOLO TIME: I AM PROUD OF MYSELF I AM A GOOD STUDENT WITH RESPECT FOR ME AND OTHERS.
EXIT PASS: • WRITE TWO EQUATIONS THAT ARE PARALLEL