What are the possible values of x in x2 + 3x + 3 = 0?

A.
`(-2 stackrel(+)(-) isqrt(3))/(3)`

B.
`(-3 stackrel(+)(-) isqrt(12))/(2)`

C.
`(-3 stackrel(+)(-) isqrt(3))/(2)`

D.
`(3 stackrel(+)(-) isqrt(3))/(2)`

Respuesta :

To solve a quadratic equation like [tex] ax^2+bx+c=0 [/tex], you can use the quadratic formula

[tex] x_{1,2} = \cfrac{-b\pm\sqrt{b^2-4ac}}{2a} [/tex]

In your case, [tex] a = 1, b = c = 3 [/tex], so the formula becomes

[tex] x_{1,2} = \cfrac{-3\pm\sqrt{(-3)^2-4\cdot 1\cdot 3}}{2\cdot 1} [/tex]

We can simplify the expression:

[tex] x_{1,2} = \cfrac{-3\pm\sqrt{9-12}}{2} = \cfrac{-3\pm\sqrt{-3}}{2}[/tex]

Since -3 is negative, its square root is computed as

[tex] \sqrt{-3} = \sqrt{-1\cdot 3} = \sqrt{-1}\sqrt{3} = \sqrt{3}i [/tex]

So, the solutions are

[tex] x = \cfrac{-3+i\sqrt{3}}{2} \text{ or } x = \cfrac{-3-i\sqrt{3}}{2} [/tex]

Answer:


Step-by-step explanation:

The answer is C. `(-3 stackrel(+)(-) isqrt(3))/(2)`