Question

The roots of the equation x power 4 - 8 x square - 9 = 0 are ​

Answer 1

Step-by-step explanation:

${x}^{4} - 8 {x}^{2} - 9 = 0 \\ let \: {x \:}^{2} = a \\ {a}^{2} - 8a - 9 = 0 \\ {a}^{2} - 9a +a - 9 \\ a(a - 9) + 1(a - 9) \\ (a - 9)(a + 1) \\ so \: \: a = 9 \: or \: - 1 \\n ow \\ {x}^{2} = a = 9 \\ so \: x = + - 3 \\ or \\ x = \sqrt{ - 1} = i$

Answer 2

Step-by-step explanation:

refer the attachment for the answer

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