document.write( "Question 861377: If one root of a quadratic equation is 3 and the product of the roots is 15, what is the value of b if the equation is in the form $\"+ax%5E2%2Bbx%2Bc+=+0+\"$ and a=1? \n" ); document.write( "

Algebra.Com's Answer #518989 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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If one root of a quadratic equation is 3 and the product of the roots is 15, what is the value of b if the equation is in the form ax^2 + bx + c = 0 and a=1?
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\n" ); document.write( "15/3 = 5 is the other root
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\n" ); document.write( "(x-3)*(x-5) = x^2 - 8x + 15
\n" ); document.write( "b = -8
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