document.write( "Question 1160833: Find the point on the line y=4x that is closest to the point P=(1,2). \n" ); document.write( "
Algebra.Com's Answer #784235 by MathLover1(20850)\"\" \"About 
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the point on the line \"y=4x\" that is closest to the point \"P\"=(\"1\",\"2\") will be intersection point of the line \"y=4x\" and the line perpendicular to \"y=4x\" that passes through the point \"P\"=(\"1\"},\"2\") \r
\n" ); document.write( "\n" ); document.write( "the line \"y=4x\" have a slope \"m=4\"\r
\n" ); document.write( "\n" ); document.write( "and the perpendicular line will have a slope negative reciprocal which is \"-1%2F4\"\r
\n" ); document.write( "\n" ); document.write( "then, the equation of the perpendicular line will be\r
\n" ); document.write( "\n" ); document.write( "\"y=-%281%2F4%29x%2Bb\"......use given point \"P\"=(\"1\"},\"2\") to calculate \"b\"\r
\n" ); document.write( "\n" ); document.write( "\"2=-%281%2F4%291%2Bb\"\r
\n" ); document.write( "\n" ); document.write( "\"2%2B%281%2F4%29=b\"\r
\n" ); document.write( "\n" ); document.write( "\"9%2F4=b\"\r
\n" ); document.write( "\n" ); document.write( "the equation of the perpendicular line is:\r
\n" ); document.write( "\n" ); document.write( "\"y=-%281%2F4%29x%2B9%2F4\"\r
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\n" ); document.write( "\n" ); document.write( "now find intersection point \"I\" solving the system:\r
\n" ); document.write( "\n" ); document.write( "\"y=4x\".........eq.1\r
\n" ); document.write( "\n" ); document.write( "\"y=-%281%2F4%29x%2B9%2F4\"....eq.2
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\n" ); document.write( "\"4x=-%281%2F4%29x%2B9%2F4\"\r
\n" ); document.write( "\n" ); document.write( "\"4x%2B%281%2F4%29x=9%2F4\"....both sides multiply by \"4\"\r
\n" ); document.write( "\n" ); document.write( "\"16x%2Bx=9\"\r
\n" ); document.write( "\n" ); document.write( "\"17x=9\"\r
\n" ); document.write( "\n" ); document.write( "\"x=9%2F17\"-> \"x\" coordinate\r
\n" ); document.write( "\n" ); document.write( "\"y=4%289%2F17%29=36%2F17\"->\"y\" coordinate\r
\n" ); document.write( "\n" ); document.write( "intersection point: \"I\"=(\"9%2F17\",\"36%2F17\")\r
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