document.write( "Question 66525: solve
\n" ); document.write( "X^4-10x^2+9=0
\n" ); document.write( "and
\n" ); document.write( "y-2-8(sqrt)(y-2)+15=0\r
\n" ); document.write( "\n" ); document.write( "Thanks! \n" ); document.write( "

Algebra.Com's Answer #47184 by Nate(3500) $\"\"$ $\"About$

You can put this solution on YOUR website!
x^4 - 10x^2 + 9 = 0
\n" ); document.write( "To make it much easier, denote x^2 = y ....
\n" ); document.write( "(x^2)^2 - 10(x^2) + 9 = 0
\n" ); document.write( "(y)^2 - 10(y) + 9 = 0
\n" ); document.write( "y^2 - 10y + 9 = 0
\n" ); document.write( "(y - 9)(y - 1) = 0
\n" ); document.write( "(x^2 - 9)(x^2 - 1) = 0
\n" ); document.write( "(x + 3)(x - 3)(x + 1)(x - 1) = 0
\n" ); document.write( "x = -3
\n" ); document.write( "x = 3
\n" ); document.write( "x = -1
\n" ); document.write( "x = 1
\n" ); document.write( " $\"graph%28300%2C300%2C-5%2C5%2C-6%2C6%2Cx%5E4+-+10x%5E2+%2B+9%29\"$
\n" ); document.write( "~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
\n" ); document.write( "y - 2 - 8*sqrt(y - 2) + 15 = 0
\n" ); document.write( "sqrt(y - 2) = (y + 13)/8
\n" ); document.write( "y - 2 = (y^2 + 26y + 169)/64
\n" ); document.write( "64y - 128 = y^2 + 26y + 169
\n" ); document.write( "0 = y^2 - 38y + 297
\n" ); document.write( "0 = (y^2 - 11y) + (-27y + 297)
\n" ); document.write( "0 = y(y - 11) - 27(y - 11)
\n" ); document.write( "0 = (y - 27)(y - 11)
\n" ); document.write( "y = 27 and y = 11
\n" ); document.write( " $\"graph%28500%2C500%2C-8%2C30%2C-15%2C15%2Cx+-+2+-+8%2Asqrt%28x+-+2%29+%2B+15%29\"$ \n" ); document.write( "

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