document.write( "Question 269533: (x^2)^2-7x^2-8=0 \n" ); document.write( "

Algebra.Com's Answer #197539 by drk(1908) $\"\"$ $\"About$

You can put this solution on YOUR website!
Let Y = x^2 and Y^2 = x^4. We get
\n" ); document.write( "Y^2 - 7Y - 8 = 0
\n" ); document.write( "factoring, we get
\n" ); document.write( "(Y-8)(Y+1) = 0
\n" ); document.write( "solving each for Y, we get
\n" ); document.write( "Y = 8 and
\n" ); document.write( "Y = -1
\n" ); document.write( "re-substitute x^2 for Y and we get
\n" ); document.write( "x^2 = 8 - - - > X = 2sqrt(2)
\n" ); document.write( "x^2 = -1 - - -> no solution \n" ); document.write( "

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