SOLUTION: Find K so that the line through (4,4) and (k,8) is A) parallel to 3y-4x=8 B) perpenidcular to 4y+5x=3

Algebra ->  Linear-equations -> SOLUTION: Find K so that the line through (4,4) and (k,8) is A) parallel to 3y-4x=8 B) perpenidcular to 4y+5x=3      Log On


   

Question 1049957: Find K so that the line through (4,4) and (k,8) is
A) parallel to 3y-4x=8
B) perpenidcular to 4y+5x=3
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
(A)
+3y+-+4x+=+8+
+3y+=+4x+%2B+8+
+y+=+%284%2F3%29%2Ax+%2B+8%2F3+
------------------------
The slope of the line through
( 4,4 ) and ( k,8 ) is:
+m+=+%28+8+-+4+%29+%2F+%28+k+-+4+%29+
+m+=+4+%2F+%28+k+-+4+%29+
----------------------------
A line parallel to the given line
will have the same slope
+4+%2F+%28+k-4+%29+=+4%2F3+
+k+-+4+=+3+
+k+=+7+
----------------------
----------------------
(B)
+4y+%2B+5x+=+3+
+4y+=+-5x+%2B+3+
+y+=+-%285%2F4%29%2Ax+%2B+3%2F4+
+m%5B1%5D+=+-%285%2F4%29+
Any line perpendicular to this line
will have slope:
+m%5B2%5D+=+-1%2Fm%5B1%5D+
+m%5B2%5D+=+-1%2F%28-%285%2F4%29%29+
+m%5B2%5D+=+4%2F5+
+4%2F%28+k-4+%29+=+4%2F5+
+k+-+4+=+5+
+k+=+9+