In the xy plane line m has the equation 4x + y = k. Line n passes through the origin and is perpendicular to line m. If point p has the coordinates (r, r+1) and is on both line n and m what is the value of r?
Can anybody help me with this problem?! I really have no idea how to attack this problem..
You can approach by calculating slopes of both lines m and n.
As we know both m and n lines are perpendicular; slope m* slope n= -1
slope of m= -4 since 4x=y+k =>(Y=m
x+c), where m
now calculate slope of n. as we know line passes through origin (0,0) and (r, r+1)
slope = (y2-y1)/(x2-x1) => (r+1-0)/(r-0) => (r+1)/r
lines are perpendicular; thus we can multiply both slopes
(r+1)/r*-4=-1 gives r= -4/3
Hence Ans is A.
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