document.write( "Question 812942: Solve
\n" ); document.write( "a) x^(1/2) - x^(1/4) - 2 = 0\r
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\n" ); document.write( "\n" ); document.write( "Can you please help me out? Thanks so much in advance:)
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Algebra.Com's Answer #489447 by jsmallt9(3758)\"\" \"About 
You can put this solution on YOUR website!
\"x%5E%281%2F2%29-x%5E%281%2F4%29-2=0\"
\n" ); document.write( "Since the first exponent, 1/2, is twice the second exponent, 1/4, then this equation is what is known as \"quadratic form\". These types of equations can be solved using techniques that are used to solve regular quadratic equations.

\n" ); document.write( "Until you have had some practice with these equations they can be difficult. It can help to use a temporary variable. Set it to the variable and exponent in the middle:
\n" ); document.write( "Let \"q+=+x%5E%281%2F4%29\"
\n" ); document.write( "Then \"q%5E2+=+%28x%5E%281%2F4%29%29%5E2+=+x%5E%281%2F2%29\"
\n" ); document.write( "Substituting these into your equation we get:
\n" ); document.write( "\"q%5E2+-q+-2+=+0\"
\n" ); document.write( "This now actually looks like a quadratic equation. It will factor:
\n" ); document.write( "(q+1)(q-2) = 0
\n" ); document.write( "From the Zero Product Property:
\n" ); document.write( "q+1 = 0 or q-2 = 0
\n" ); document.write( "Solving these we get:
\n" ); document.write( "q = -1 or q = 2

\n" ); document.write( "We have solved for our made-up variable q. But we really want solutions for x. At this point we substitute back in for the q:
\n" ); document.write( "\"x%5E%281%2F4%29+=+-1\" or\"x%5E%281%2F4%29+=+2\"
\n" ); document.write( "And last of all we solve for x.

\n" ); document.write( "The first equation says that a 4th root is equal to a negative number. 4th roots (without a minus in front) must be positive so we will not get any (real) solutions from the first equation.

\n" ); document.write( "To solve the second equation we just raise each side to the 4th power:
\n" ); document.write( "\"%28x%5E%281%2F4%29%29%5E4+=+2%5E4\"
\n" ); document.write( "which simplifies to:
\n" ); document.write( "x = 16

\n" ); document.write( "Since we raised each side of an equation by an even power we should check. Use the original equation:
\n" ); document.write( "\"x%5E%281%2F2%29-x%5E%281%2F4%29-2=0\"
\n" ); document.write( "Checking x = 16:
\n" ); document.write( "\"%2816%29%5E%281%2F2%29-%2816%29%5E%281%2F4%29-2=0\"
\n" ); document.write( "Since 1/2 as an exponent means square root and an exponent of 1/4 means 4th root and since we know both the square and 4th roots of 16 this simplifies to:
\n" ); document.write( "4 - 2 - 2 = 0
\n" ); document.write( "which further simplifies to:
\n" ); document.write( "0 = 0 Check!

\n" ); document.write( "P.S. Once you get some practice with these you will no longer need the temporary variable. You will start seeing how to go directly from
\n" ); document.write( "\"x%5E%281%2F2%29-x%5E%281%2F4%29-2=0\"
\n" ); document.write( "to
\n" ); document.write( "\"%28x%5E%281%2F4%29%2B1%29%28x%5E%281%2F4%29-2%29+=+0\"
\n" ); document.write( "to
\n" ); document.write( "\"x%5E%281%2F4%29%2B1+=+0\" or \"x%5E%281%2F4%29-2+=+0\"
\n" ); document.write( "etc.
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