document.write( "Question 548218: Write a quadratic function in standard form with zeros 6 and -8? \n" ); document.write( "
Algebra.Com's Answer #356797 by mathie123(224)\"\" \"About 
You can put this solution on YOUR website!
We know if the quadratic function has zeros 6 and -8 then
\n" ); document.write( "x-6 and x-(-8)=x+8 are both factors of the quadratic function This means that \r
\n" ); document.write( "\n" ); document.write( "\"y=%28x-6%29%28x%2B8%29\" \r
\n" ); document.write( "\n" ); document.write( "Now... standard form is also known as vertex form and is written as
\n" ); document.write( "\"y=a%28x-h%29%5E2%2Bk\"\r
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\n" ); document.write( "\n" ); document.write( "We can expand our quadratic from above and then put it into this form:\r
\n" ); document.write( "\n" ); document.write( "\"y=%28x-6%29%28x%2B8%29\"
\n" ); document.write( "\"y=x%5E2%2B8x-6x-48\"
\n" ); document.write( "\"y=x%5E2%2B2x-48\"\r
\n" ); document.write( "\n" ); document.write( "Now we must complete the square to get it into standard form. To do this, we must add half of the b value squared ((half of 2 is 1 and 1 squared is 1 so we add one). If we add 1, we must subtract it as well (so we are essentially not changing the equation).
\n" ); document.write( "\"y=x%5E2%2B2x-48\"
\n" ); document.write( "\"y=x%5E2%2B2x%2B1-48-1\"
\n" ); document.write( "Now taking the first three terms, they can be factored as so:
\n" ); document.write( "\"y=%28x%2B1%29%5E2-48-1\"
\n" ); document.write( "\"y=%28x%2B1%29%5E2-49\"\r
\n" ); document.write( "\n" ); document.write( "there we have it:) \r
\n" ); document.write( "\n" ); document.write( "Let me know if you are unsure about anything and I will make sure it is clear for you :)
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