In the xy plane line m has the equation 4x + y = u. 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?
Choose one:  A) -4/3  B) 1/4  C) -4  D) 3/4  E) 4/3
The equation of line m is y=-4x+u. Now, since line n is perpendicular to line m, then its slope is negative reciprocal of the slope of line m, so the slope of n is 1/4. Next, as line n passes through the origin (0, 0) and has the slope of 1/4 then its equation is y=1/4*x.   Point (r, r+1) lies on line n means that (r+1)=1/4*r --&gt; r( +1)= 
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1/4*r --&gt; r=-4/3.   -4/3nswer: -4/3.
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In the xy plane line m has the equation 4x + y = u. 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?