Math quadratic HELP ! TODAY!!

Let the number be x
x + 1/x = 29/10
x^2 + 1 = 29x/10
10x^2 + 10 = 29x
10x^2 - 29x + 10 = 0
10x^2 - 25x - 4x + 10 = 0
5x(2x - 5) - 2(2x - 5) = 0
(5x - 2)(2x - 5) = 0
x = 2/5 or x = 5/2

2009-11-22 16:09:51 補充：
x^4 + 10x^2 + 25 = 0
(x^2 + 5)^2 = 0
x^2 + 5 = 0
x = +/-√5 i
(x^2 - 2x)^2 + 5(x^2-2x) + 6 = 0
Let y = x^2 - 2x
y^2 + 5y + 6 = 0
(y + 2)(y + 3) = 0
x^2 - 2x + 2 = 0 or x^2 - 2x + 3 = 0
x = [2+/-√(4-8)]/2 or x = [2+/-√(4-12)]/2
x = 1 +/- i or x = 1 +/- √2 i

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