document.write( "Question 1019836: Find the equation of the circle touching the line 4x-3y=28 at (4,-4) and passing through (-3,-5).
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Algebra.Com's Answer #635768 by Alan3354(69443)\"\" \"About 
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Find the equation of the circle touching the line 4x-3y=28 at (4,-4) and passing through (-3,-5).
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\n" ); document.write( "The center of the circle is on the line perpendicular to the given line thru (4,-4).
\n" ); document.write( "The slope of the line is -3/4 --> y+4 = (-3/4)*(x-4)
\n" ); document.write( "--> y = -3x/4 - 1
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\n" ); document.write( "The slope of a line tangent to a circle is -x/y.
\n" ); document.write( "The center of the circle is also on the line perpendicular to the tangent line thru (-3,-5).
\n" ); document.write( "The slope of the tangent line = -3/5.
\n" ); document.write( "The slope of the line perpendicular = 5/3
\n" ); document.write( "--> y+5 = (5/3)*(x+3)
\n" ); document.write( "--> y = 5x/3
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\n" ); document.write( "The center of the circle is the intersection of y = 5x/3 and y = -3x/4 - 1
\n" ); document.write( "5x/3 = -3x/4 - 1
\n" ); document.write( "20x = -9x - 12
\n" ); document.write( "x = -12/29 --> y = -20/29
\n" ); document.write( "Center at (-12/29,-20/29)
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\n" ); document.write( "r = distance from the center to (4,-4)
\n" ); document.write( "\"r%5E2+=+%28-4%2B20%2F29%29%5E2+%2B+%284%2B12%2F29%29%5E2+=+%2896%5E2+%2B+128%5E2%29%2F841\"
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\n" ); document.write( "\"%28x+%2B+12%2F29%29%5E2+%2B+%28y+%2B+20%2F29%29%5E2+=+%28160%2F29%29%5E2\"
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\n" ); document.write( "Something is wrong, I'll check it later.
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\n" ); document.write( "I can't find the error. If you can't find it, repost it, maybe someone else will do it.
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\n" ); document.write( "I see what the problem is. A slope of -x/y for a circle applies to circles centered at the Origin.
\n" ); document.write( "I'll work on this later today.
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