3. Writing Equations of Parallel and Perpendicular Lines
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Lines a and b are parallel.
Lines are parallel if their slopes are identical. Let's recall the slope-intercept form of a line.
| Line | Given Equation | Slope-Intercept Form | Slope |
|---|---|---|---|
| a | 3y-x=6 | y=1/3x+2 | 1/3 |
| b | 3y=x+18 | y=1/3x+6 | 1/3 |
| c | 3y-2x=9 | y=2/3x+3 | 2/3 |
Now that we have identified the slope of each line, we can see that a and b have the same slope, so we know that they are parallel.