document.write( "Question 130272This question is from textbook Discovering Algebra
\n" ); document.write( ": I am supposed to \"Solve each quadratic equation by completing the square. Leave your answer in radical form.\" I'm not really sure what the radical form is. I don't even know if this question falls under the section of quadratic equation or radicals. My textbook says I need to complete the square or something. The equation is $\"x%5E2-4x-8=0\"$ . I tried to solve it symbollically (I think..) and I: added the 8 to the zero, square-rooted the whole thing and somehow I ended up with $\"x-4x=_%2B4\"$ . I'm not sure if I'm done or not... Please help! \n" ); document.write( "

Algebra.Com's Answer #95145 by Earlsdon(6294) $\"\"$ $\"About$

You can put this solution on YOUR website!
Solve by completing the square:
\n" ); document.write( " $\"x%5E2-4x-8+=+0\"$
\n" ); document.write( "Here's how you do \"completing the square\"
\n" ); document.write( "First, add 8 to both sides.
\n" ); document.write( " $\"x%5E2-4x+=+8\"$ Now, add the square of half the x-coefficient, that's $\"%284%2F2%29%5E2+=+4\"$ to both sides of the equation.
\n" ); document.write( " $\"x%5E2-4x%2B4+=+8%2B4\"$ Factor the left side and simplify the right side.
\n" ); document.write( " $\"%28x-2%29%28x-2%29+=+12\"$ So there's the square on the left side, see it?
\n" ); document.write( " $\"%28x-2%29%5E2+=+12\"$ Now take the square root of both sides.
\n" ); document.write( " $\"x-2+=+sqrt%2812%29\"$ Plus or minus. Now add 2 to both sides.
\n" ); document.write( " $\"x+=+2%2B-sqrt%2812%29\"$ The right side can be simplified because: $\"sqrt%2812%29+=+sqrt%284%2A3%29\"$ = $\"2sqrt%283%29\"$ , so...
\n" ); document.write( " $\"x+=+2%2B2sqrt%283%29\"$ or $\"x+=+2-2sqrt%283%29\"$ This is in \"radical form\"
\n" ); document.write( "Leaving the answer in \"radical form\" simply means don't take the square root of the answer but leave it with the square root (radical) symbol. \n" ); document.write( "

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