Question

What are the solutions of the equation x^4+3x^2+2=0? Use u substitution to solve.

Answer 1

• Option B

Explanation:

Solve the equation in steps below

• 
  `x^4+3x^2+2=0`
• 
  `x^4+x^2+2x^2+2=0`
• 
  `x^2(x^2+1)+2(x^2+1)=0`
• 
  `(x^2+2)(x^2+1) = 0`
• 
  `x^2+2=0` or
  `x^2+1=0`
• 
  `x^2=-2` or
  `x^2=-1`
• 
  `x=√(-2)` or
  `x=√(-1)`
• 
  `x=\pm\ i√(2)` or
  `x=\pm\ i`

Correct choice is B