document.write( "Question 871498: Solve step by step :-
\n" ); document.write( "9d^4-490d^2+490=0 \n" ); document.write( "

Algebra.Com's Answer #525577 by Fombitz(32388) $\"\"$ $\"About$

You can put this solution on YOUR website!
Substitute $\"u=d%5E2\"$
\n" ); document.write( " $\"9u%5E2-490u%2B490=0\"$
\n" ); document.write( " $\"9%28u%5E2-%28490%2F9%29u%2B%28245%2F9%29%5E2%29%2B490=9%28245%2F9%29%5E2\"$
\n" ); document.write( " $\"9%28u-%28245%2F9%29%29%5E2=9%28245%2F9%29%5E2-490\"$
\n" ); document.write( " $\"%28u-245%2F9%29%5E2=%28245%2F9%29%5E2-490%2F9\"$
\n" ); document.write( " $\"%28u-245%2F9%29%5E2=60025%2F81-4410-81\"$
\n" ); document.write( " $\"%28u-245%2F9%29%5E2=55615%2F81\"$
\n" ); document.write( " $\"u-245%2F9=0+%2B-+sqrt%2855615%29%2F9\"$
\n" ); document.write( " $\"u=245%2F9+%2B-+%287%2F9%29sqrt%281135%29\"$
\n" ); document.write( " $\"d%5E2=245%2F9+%2B-+%287%2F9%29sqrt%281135%29\"$
\n" ); document.write( "Both values are positive.
\n" ); document.write( " $\"d=sqrt%28245%2F9+%2B-+%287%2F9%29sqrt%281135%29%29%29\"$
\n" ); document.write( " \n" ); document.write( "

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