What are the solutions of the equation x^4-9x^2+8=0? Use u substitution to solve.

asked Oct 3, 2023 50.8k views

16 votes

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7 votes

Answer:

The answer is the second option

Explanation:

Let u=x^2.

$( {x}^(2) ) {}^(2) - 9( {x}^(2) ) + 8( {x}^(2) ) {}^(0)$

${u}^(2) - 9u + 8$

(u - 1)(u - 8)

u = 1

u = 8

Set this equal to x^2

${x}^(2) = 1$

x = 1

x = - 1

${x}^(2) = 8$

x = 2 √(2)

x = - 2 √(2)

Aladdin answered Oct 6, 2023

4.1k points

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