document.write( "Question 387399: The homework question is,Show that the line with equation y=2x-10 is a tangent to the circle with equation x2+y2-4x+2y=0 and establish the coordinates of the point of contact. x2 means x squared and y2 means y squared. Can you provide a solution with working please?\r
\n" ); document.write( "\n" ); document.write( "Many Thanks,
\n" ); document.write( " Andrew.
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Algebra.Com's Answer #273871 by scott8148(6628)\"\" \"About 
You can put this solution on YOUR website!
substituting ___ x^2 + (2x - 10)^2 - 4x + 2(2x - 10) = 0\r
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\n" ); document.write( "\n" ); document.write( "x^2 + 4x^2 - 40x + 100 - 4x + 4x - 20 = 0\r
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\n" ); document.write( "\n" ); document.write( "5x^2 - 40x + 80 = 0\r
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\n" ); document.write( "\n" ); document.write( "x^2 - 8x + 16 = 0\r
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\n" ); document.write( "\n" ); document.write( "(x - 4)^2 = 0\r
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\n" ); document.write( "\n" ); document.write( "x = 4\r
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\n" ); document.write( "\n" ); document.write( "y = 2(4) - 10 = -2\r
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\n" ); document.write( "\n" ); document.write( "since there is only one solution for x , there is only one point of contact between the line and the circle
\n" ); document.write( "this defines the tangent\r
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\n" ); document.write( "\n" ); document.write( "the point of tangency is (4,-2)
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