document.write( "Question 696969: Find all zeros of f(x)=3x^3+9x^2-5x-15 \n" ); document.write( "

Algebra.Com's Answer #429556 by MathLover1(20850) $\"\"$ $\"About$

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\n" ); document.write( "\n" ); document.write( " $\"f%28x%29=3x%5E3%2B9x%5E2-5x-15\"$ ...set $\"f%28x%29\"$ equal to zero\r
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\n" ); document.write( "\n" ); document.write( " $\"3x%5E3%2B9x%5E2-5x-15=0\"$ ...factor\r
\n" ); document.write( "\n" ); document.write( " $\"%283x%5E3-5x%29%2B%289x%5E2-15%29=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"x%283x%5E2-5%29%2B3%283x%5E2-5%29=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"%28x%2B3%29%283x%5E2-5%29=0\"$ \r
\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "if $\"x%2B3=0\"$ ....=>... $\"highlight%28x=-3%29\"$ \r
\n" ); document.write( "\n" ); document.write( "if $\"3x%5E2-5=0\"$ ...=>... $\"3x%5E2=5\"$ ..=>... $\"x%5E2=5%2F3\"$ ..=>... $\"highlight%28x=sqrt%285%2F3%29%29\"$ and $\"highlight%28x=-sqrt%285%2F3%29%29\"$ \r
\n" ); document.write( "\n" ); document.write( "or $\"sqrt%285%2F3%29=1.29\"$ , so we have\r
\n" ); document.write( "\n" ); document.write( " $\"highlight%28x=1.29%29\"$ and $\"highlight%28x=-1.29%29\"$ \r
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