 # Questions from 1.5 HW???.

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Questions from 1.5 HW???

1.6 Graph Using Slope-Intercept Form
No School Monday: 1/18/10 Quiz: 1/22/10 Unit 1 Test: 1/27/10

Vocabulary A linear equation of the form y = mx + b is written in slope-intercept form, where m is the slope and b is the y-intercept of the equation’s graph. y = mx + b SLOPE y-intercept

Both lines have a slope of 3. So the lines are PARALLEL
Vocabulary Two lines are parallel if the do NOT intersect. Parallel lines have the SAME slope. Ex: y = 3x – 2 and y = 3x + 5 Both lines have a slope of 3. So the lines are PARALLEL

What is a negative reciprocal??
Vocabulary What is a negative reciprocal?? Two lines are perpendicular if they intersect to form a right angle. Perpendicular lines have slopes that are negative reciprocals. Ex: y = 2x – 3 and y = -1/2x -7 2 and -1/2 are negative reciprocals. So the lines are PERPENDICULAR

Example 1: Identify the slope and y-intercept of the line with the given equation. Y = 1/4x – 2 -2x + 3y = 9 (what do we need to do to this equation before we can identify slope and the y-intercept?)

Your Turn: Identify the slope and y-intercept of the line with the given equation: Y = -3x + 7 Y = 4x – 10 15x – 5y = 10 Y = 5 – 7x

Example 2: Graph the equation 4x + y = 3 (using the slope and y-intercept)

**We need to find the slope of each line and then compare**
Example 3: Determine which of the lines are parallel or perpendicular: line a through (-4, 1) and (-6, 7) line b through (-7, -5) and (1, 11) line c through (2, 5) and (4, 9) line d through (4, 3) and (10, 5) **We need to find the slope of each line and then compare**

Example 3 continued: Find the slope of line a:
Parallel Lines: have the SAME slope Perpendicular Lines: have NEGATIVE RECIPROCALS as their slopes Example 3 continued: Find the slope of line a: Find the slope of line b: Find the slope of line c: Find the slope of line d:

Your Turn: Graph the equation y = 3/4x – 1

Homework: P #2-22even, 27-32