SOLUTION: Please help me find the equation of the line perpendicular to -4x-8y=-5 that contains the point (-2,5). A.y=1/2x+6 B.y=2x+1 C.y=-2x+1 D.y=2x+9

Algebra ->  Equations -> SOLUTION: Please help me find the equation of the line perpendicular to -4x-8y=-5 that contains the point (-2,5). A.y=1/2x+6 B.y=2x+1 C.y=-2x+1 D.y=2x+9      Log On


   

Question 550522: Please help me find the equation of the line perpendicular to -4x-8y=-5 that contains the point (-2,5).
A.y=1/2x+6
B.y=2x+1
C.y=-2x+1
D.y=2x+9
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
+-4x+-+8y+=+-5+
First, multiply both sides by +-1+
+4x+%2B+8y+=+5+
+8y+=+-4x+%2B+5+
+y+=+%28-1%2F2%29%2Ax+%2B+5%2F8+
This is in the form +y+=+mx+%2B+b+
where +m+=+-1%2F2+
Any line which is perpendicular to this line
will have slope = +-1%2Fm+
+-1%2Fm+=+-1%2F%28-1%2F2%29+
+-1%2Fm+=+2+
------------------
So far I have +y+=+2x+%2B+b+
I need to find b
Plug in the point (-2,5)
+5+=+2%2A%28-2%29+%2B+b+
+5+=+-4+%2B+b+
+b+=+9+
The equation is D:+y+=+2x+%2B+9+