document.write( "Question 1196945: Determine the zeros of the f(x)=x^2-3x-4 then estimate the instantaneous rate of change in f(x) at the zeros\r
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Algebra.Com's Answer #829997 by MathLover1(20850) $\"\"$ $\"About$

You can put this solution on YOUR website!
to determine the zeros of the $\"f%28x%29=x%5E2-3x-4\"$ , set $\"f%28x%29=0\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"0=x%5E2-3x-4\"$ ...........factor\r
\n" ); document.write( "\n" ); document.write( " $\"0=x%5E2%2Bx-4x-4\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"0=%28x%5E2%2Bx%29-%284x%2B4%29\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"0=x%28x%2B1%29-4%28x%2B1%29\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"0+=+%28x+-+4%29%28x+%2B+1%29\"$ \r
\n" ); document.write( "\n" ); document.write( "solutions:\r
\n" ); document.write( "\n" ); document.write( "if $\"0+=+%28x+-+4%29\"$ => $\"x=4\"$ \r
\n" ); document.write( "\n" ); document.write( "if $\"0+=+%28x+%2B+1%29\"$ => $\"x=-1\"$ \r
\n" ); document.write( "\n" ); document.write( "so, zeros are $\"-1\"$ and $\"4\"$ \r
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\n" ); document.write( "\n" ); document.write( " $\"+graph%28+600%2C+600%2C+-10%2C+10%2C+-10%2C+10%2C+x%5E2-3x-4%29+\"$ \r
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\n" ); document.write( "\n" ); document.write( "the instantaneous rate of change in $\"f%28x%29\"$ at the zeros:\r
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\n" ); document.write( "\n" ); document.write( "∆y/∆x= $\"%28f%28x2%29+-f%28x1%29+%29%2F%28x2+-+x1+%29\"$ \r
\n" ); document.write( "\n" ); document.write( "∆y/∆x= $\"%28f%284%29+-f%28-1%29+%29%2F%284+-+1+%29\"$ \r
\n" ); document.write( "\n" ); document.write( "∆y/∆x= $\"%28f%284%29+-f%28-1%29+%29%2F3\"$ \r
\n" ); document.write( "\n" ); document.write( "find $\"f%284%29\"$ and $\"f%28-1%29\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"f%284%29=4%5E2-3%2A4-4=0\"$ \r
\n" ); document.write( "\n" ); document.write( " $\"f%28-1%29=%28-1%29%5E2-3%28-1%29-4=0\"$ \r
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\n" ); document.write( "\n" ); document.write( "∆y/∆x= $\"%280+-0+%29%2F3=0%2F3=0\"$ \r
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