Question 197385
10x^4 -19x^2 +6 = 0
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Let  y=x^2
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10 y^2 -19y + 6 = 0
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(5y-2)(2y-3) = 0
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y= 2/5,  3/2
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but  y=x^2
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x^2 =  2/5 , 3/2
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x = sqrt 2/5 = +/-  .632,,,,,or  y= sqrt 3/2 =  +/-  1.225
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checking
10(.632^4) -19(.632^2)  + 6 = 0,,,ok
10(1.225^4) -19(1.225^2) +6 = 0 ,,,ok