Respuesta :
Answer:
Parallel: The slope is the same as in the previous equation. So, y=3x+b. To find the value of b, you plug in the given point, 2=3(3)+b, b=-7. So the equation is y=3x-7.
Perpendicular: The slope is the negative reciprocal when an equation is perpendicular. The negative reciprocal of -2 is 1/2. So, y=1/2x+b. To find the value of b, you plug in the given point, -1=1/2(2)+b, -1=1+b, b=-2. So the equation is y=1/2x-2.
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9514 1404 393
Answer:
- parallel: y = 3x -7
- perpendicular: y = 1/2x -2
Step-by-step explanation:
The given line equations are written in "slope-intercept" form.
y = mx + b . . . . . . . . . m is the slope; b is the y-intercept
If we solve this equation for b, we find ...
b = y - mx
This is useful for completing the equation of the line through a given point when the slope is known.
Parallel
A parallel line will have the same slope as the given line. The given line has a slope (x-coefficient) of 3. We can find the "b" of the line through the desired point as ...
b = y -3x
b = 2 -(3)(3) = -7
The equation of the parallel line is ...
y = 3x -7
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Perpendicular
A perpendicular line will have a slope that is the opposite reciprocal of the slope of the line it is perpendicular to. Here, the given line has a slope of -2, so the perpendicular line will have a slope of ...
-1/(-2) = 1/2
Then the y-intercept is ...
b = y -(1/2)x
b = -1 -(1/2)(2) = -2
And the equation of the perpendicular line is ...
y = 1/2x -2
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The attached graph shows the original lines as dashed lines, and the corresponding desired lines as solid lines in the same color.
