document.write( "Question 252782: A road is to be constructed perpendicular to an established road. A surveyor determines that the original road passes through the points (4,9) and (2,13). The roads must intersect at (4,9) Write the equation of the second road. \n" ); document.write( "
Algebra.Com's Answer #184904 by checkley77(12844)\"\" \"About 
You can put this solution on YOUR website!
I always thought perpendicular meant at right angles rather than parallel?\r
\n" ); document.write( "\n" ); document.write( "First road slope:
\n" ); document.write( "Slope=(13-9)/(2-4)=4/-2=-2
\n" ); document.write( "Equation for the original road:
\n" ); document.write( "y=-2x+9 (red line)
\n" ); document.write( "Parallel road slope=-2
\n" ); document.write( "Y=mX+b
\n" ); document.write( "9=-2*4+b
\n" ); document.write( "9=-8+b
\n" ); document.write( "b=9+8
\n" ); document.write( "b=17 is the Y intercept of the parallel road.
\n" ); document.write( "Equation for the pasrallel road. (green line)
\n" ); document.write( "\"+graph%28+300%2C+200%2C+-6%2C+10%2C+-10%2C+20%2C+-2x+%2B9%2C+-2x+%2B17%29+\" (graph 300x200 pixels, x from -6 to 10, y from -10 to 20, of TWO functions -2x +9 and -2x +17). \r
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