document.write( "Question 252418: Find the value(s) of k such that the equation f(x + k) = 0 has two equal real roots.\r
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document.write( "f(x) = - (1/2)x^2 - 5x + 4\r
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document.write( "please show steps, thank you so much! \n" );
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Algebra.Com's Answer #184348 by stanbon(75887)![]() ![]() ![]() You can put this solution on YOUR website! Find the value(s) of k such that the equation f(x + k) = 0 has two equal real roots. \n" ); document.write( "f(x) = - (1/2)x^2 - 5x + 4 \n" ); document.write( "--------------------------------- \n" ); document.write( "Find f(x+k): \n" ); document.write( "f(x+k) = (1/2)(x+k)^2-5(x+k)+4 \n" ); document.write( "f(x+k) = (1/2)(x^2+2kx+k^2 - 5x-5k+4 \n" ); document.write( "f(x+k) = (1/2)(x^2+(2k-5)x + (k^2-5k+4) \n" ); document.write( "f(x+k) = (1/2)x^2 + [(2k-5)/2]x + [k^2-5k+4]/2 \n" ); document.write( "---------------------------------------------------- \n" ); document.write( "You have a quadratic with \n" ); document.write( "a = 1/2 \n" ); document.write( "b = (2k-5)/2 \n" ); document.write( "c = (k^2-5k+4)/2 \n" ); document.write( "------------------------- \n" ); document.write( "Determine when f(x+k) will have two equal real roots. \n" ); document.write( "That happens when the discriminant is zero \n" ); document.write( "Solve: \n" ); document.write( "b^2-4ac = 0 \n" ); document.write( "[(2k-5)/2]^2 - 4*(1/2)(k^2-5k+4)/2 = 0 \n" ); document.write( "[(1/4)(4k^2-20k+25)]-[k^2-5k+4] = 0 \n" ); document.write( "[k^2-5k+(25/4)]-[k^2-5k+4] = 0 \n" ); document.write( "9/4 = 0 \n" ); document.write( "--------- \n" ); document.write( "Well, I get a contradiction but I may have made \n" ); document.write( "an arithmetic mistake somewhere along the line. \n" ); document.write( "Check it out and see what you get. \n" ); document.write( "=========================== \n" ); document.write( "Cheers, \n" ); document.write( "Stan H.\r \n" ); document.write( " \n" ); document.write( "\n" ); document.write( " \n" ); document.write( " |