document.write( "Question 1187623: find the value of k and the other root of 4x^2 + kx + 15=0 if 5 is one of its roots \n" ); document.write( "

Algebra.Com's Answer #818631 by ikleyn(52781) $\"\"$ $\"About$

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\n" ); document.write( "find the value of k and the other root of 4x^2 + kx + 15=0 if 5 is one of its roots
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document.write( "Let  \" t \"  be the other root.\r\n" );
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document.write( "Then, according to Vieta's theorem,   = 5t,  which implies  t =  = .\r\n" );
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document.write( "So, the other root is  .\r\n" );
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document.write( "Next, according to Vieta's theorem  (again; this time another part of the Vieta's theorem)   = 5 +  = 5  = .\r\n" );
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document.write( "So,  k = -23.\r\n" );
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document.write( "ANSWER.  k = -23;  the other root is .\r\n" );
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