SOLUTION: Find the symmetric point of P (1,1) according to the straight r: x-2y-4 = 0

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Question 1071534: Find the symmetric point of P (1,1) according to the straight r: x-2y-4 = 0
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
2y=x-4
y=x%2F2-2
The line perpendicular to this line going through (1,1) is,
y-1=-2%28x-1%29
y-1=-2x%2B2
y=-2x%2B3
Find the intersection of those two lines,
-2x%2B3=x%2F2-2
-4x%2B6=x-4
-5x=-10
x=2
Then,
y=2%2F2-2
y=1-2
y=-1
(2,-1)
So distance from (1,1) to (2,-1) is the same as the distance from (2,-1) to the symmetric point,
x:2%2B%282-1%29=2%2B1=3
y:-1%2B%28-1-1%29=-1-2=-3
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