document.write( "Question 542571: Solve the equation by making an appropriate substitution.
\n" ); document.write( "x-512-16sqrtx=0
\n" ); document.write( "here is what I have tried:
\n" ); document.write( "x^1-16x^1/2-512
\n" ); document.write( "(x^1/2)^2-16^1/2-512
\n" ); document.write( "subsitute x for u
\n" ); document.write( "u^2-16u-512
\n" ); document.write( "factor (I cannot find a factor for this problem so I divide everything by 2)
\n" ); document.write( "u^2-8u-256
\n" ); document.write( "using the formula
\n" ); document.write( "8 +-sqrt8^2-4(1)(256)/2(1)
\n" ); document.write( "8 +-sqrrt1088 / 2
\n" ); document.write( "reduced
\n" ); document.write( "4+12sqrrt17, 4-12sqrrt17
\n" ); document.write( "my answer choices are
\n" ); document.write( "{768}
\n" ); document.write( "{2068}
\n" ); document.write( "{1024}
\n" ); document.write( "{512}
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #354636 by Earlsdon(6294)\"\" \"About 
You can put this solution on YOUR website!
You're ok up the point of substituting \"u+=+x%5E%281%2F2%29\" or \"u+=+sqrt%28x%29\"
\n" ); document.write( "\"u%5E2-16u-512+=+0\" This wil factor:
\n" ); document.write( "\"%28u%2B16%29%28u-32%29+=+0\" Apply the zero product rule.
\n" ); document.write( "\"u%2B16+=+0\" or \"u-32+=+0\" so...
\n" ); document.write( "\"u+=+-16\" or \"u+=+32\" Substitute \"u+=+sqrt%28x%29\"
\n" ); document.write( "\"sqrt%28x%29+=+-16\" or \"sqrt%28x%29+=+32\" Square both sides in each case.
\n" ); document.write( "\"highlight%28x+=+256%29\" or \"highlight_green%28x+=+1024%29\"
\n" ); document.write( "You should check these solutions because, in squaring, you may have inadvertently introduced invalid solutions.
\n" ); document.write( "\"x-512-16sqrt%28x%29+=+0\" Substitute \"x+=+256\"
\n" ); document.write( "\"256-512-16sqrt%28256%29+=+0\"
\n" ); document.write( "\"256-512-16%2A16+=+0\"
\n" ); document.write( "\"256-512-256+=+0\"
\n" ); document.write( "\"-512+%3C%3E+0\"
\n" ); document.write( "\"1024-512-16sqrt%281024%29+=+0\"
\n" ); document.write( "\"1024-512-16%2A32+=+0\"
\n" ); document.write( "\"1024-512-512+=+0\"
\n" ); document.write( "\"1024-1024+=+0\" OK
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