document.write( "Question 743273: Find all solutions of the equation. Check your solutions in the original equation. (Enter your answers as a comma-separated list.)
\n" ); document.write( "x4 − 8x2 + 7 = 0 \n" ); document.write( "
Algebra.Com's Answer #452818 by lwsshak3(11628)\"\" \"About 
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Find all solutions of the equation. Check your solutions in the original equation. (Enter your answers as a comma-separated list.)
\n" ); document.write( "x4 − 8x2 + 7 = 0
\n" ); document.write( "(x^2-7)(x^2-1)=0
\n" ); document.write( "..
\n" ); document.write( "x^2-7=0
\n" ); document.write( "x^2=7
\n" ); document.write( "x=±√7
\n" ); document.write( "..
\n" ); document.write( "x^2-1=0
\n" ); document.write( "x^2=1
\n" ); document.write( "x=±1
\n" ); document.write( "solutions:
\n" ); document.write( "x=√7, -√7, 1, -1
\n" ); document.write( "..
\n" ); document.write( "check:
\n" ); document.write( "f(-√7): x^4−8x2+7=49-56+7=0
\n" ); document.write( "f(√7): x^4−8x2+7=49-56+7=0
\n" ); document.write( "f(-1): x^4−8x2+7=1-8+7=0
\n" ); document.write( "f(1): x^4−8x2+7=1-8+7=0 \n" ); document.write( "
\n" );