document.write( "Question 751745: Solve: 16x^2-72x=-85
\n" ); document.write( "Not sure if I'm suppose to factor or use the quadratic equation? Help would be appreciated! :) \n" ); document.write( "

Algebra.Com's Answer #457390 by josmiceli(19441) $\"\"$ $\"About$

You can put this solution on YOUR website!
$\"+16x%5E2-72x=-85+\"$
\n" ); document.write( "I don't know which method they want you to use, but
\n" ); document.write( "I can try completing the square
\n" ); document.write( "---------------------
\n" ); document.write( "First, divide both sides by $\"+16+\"$
\n" ); document.write( " $\"+x%5E2+-+%289%2F2%29%2Ax+=+-85%2F16+\"$
\n" ); document.write( "--------------------------
\n" ); document.write( "Take 1/2 of the coefficient of $\"+x+\"$ ,
\n" ); document.write( "square it, and add it to both sides
\n" ); document.write( " $\"+x%5E2+-+%289%2F2%29%2Ax+%2B+%289%2F4%29%5E2+=+-85%2F16+%2B+%289%2F4%29%5E2+\"$
\n" ); document.write( " $\"+x%5E2+-+%289%2F2%29%2Ax+%2B+81%2F16+=+-85%2F16+%2B+81%2F16+\"$
\n" ); document.write( " $\"+x%5E2+-+%289%2F2%29%2Ax+%2B+81%2F16+=+-4%2F16+\"$
\n" ); document.write( " $\"+%28+x+-+9%2F4+%29%5E2+=+%28+1%2F2%29%5E2+%2A+i%5E2+\"$
\n" ); document.write( "Take the square root of both sides
\n" ); document.write( " $\"+x+-+9%2F4+=+%281%2F2%29%2Ai+\"$
\n" ); document.write( " $\"+x+=+%28+9+%2B+2i+%29+%2F+4+\"$
\n" ); document.write( "and, also
\n" ); document.write( " $\"+x+=+%28+9+-+2i+%29+%2F+4+\"$
\n" ); document.write( "---------------------
\n" ); document.write( "Here's the plot:
\n" ); document.write( " $\"+graph%28+500%2C+500%2C+-2%2C+5%2C+-2%2C+8%2C+16x%5E2+-+72x+%2B+85+%29+\"$
\n" ); document.write( "Since it doesn't contact the x-axis, there are no real roots
\n" ); document.write( " \n" ); document.write( "

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