Respuesta :

Answer:

[tex]\sf x = \dfrac{-1 + i\sqrt{3} }{2} \quad or \quad \dfrac{-1 - i\sqrt{3} }{2}[/tex]

Explanation:

[tex]\sf Given : x^2 + x + 1 = 0[/tex]

Solve it using quadratic formula

[tex]\sf x = \dfrac{ -b \pm \sqrt{b^2 - 4ac}}{2a} \quad \:when\: \: ax^2 + bx + c = 0[/tex]

So, here constants are: a = 1, b = 1, c = 1

When the value's are substituted inside the formula

[tex]\sf \rightarrow x = \dfrac{-1 \pm \sqrt{1^2 - 4(1)(1)} }{2(1)}[/tex]

[tex]\sf \rightarrow x = \dfrac{-1 \pm \sqrt{-3} }{2}[/tex]

[tex]\sf \rightarrow x = \dfrac{-1 \pm i\sqrt{3} }{2}[/tex]

[tex]\sf \rightarrow x = \dfrac{-1 + i\sqrt{3} }{2} \quad or \quad \dfrac{-1 - i\sqrt{3} }{2}[/tex]

The answers are :

  1. x = -1 + √3i
  2. x = -1 - √3i

This problem can be solved using the quadratic equation.

x = -1 ± √1² - 4(1)(1) / 2a

x = -1 ± √1 - 4 / 2a

x = -1 ± √-3 / 2a

x = -1 ± i√3 / 2a (∴ i = √-1)

The possible values of x are :

  • x = -1 + √3i
  • x = -1 - √3i