Question 82998: Are the following lines parallel, perpendicular or neither?
L1 with equation x-5y=10
L2 with equation 5x+y=5 Answer by Mona27(45) (Show Source):
You can put this solution on YOUR website! To find whether two lines are parallel or perpendicular you need to find their gradient (slope) first.
In order to do that, you have to rearrange each one of your equations to make y the subject of the formula:
L1:
L2:
The gradient can now be found as the coefficient of x.
If two lines are parallel, then they have the same gradient.
If they are perpendicular, then the product of their gradients = -1
In this case, L1 has a gradient of
and L2 has a gradient of -5
Since these two have a product of -1, then the two lines are perpendicular.
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