Answered

Select the two values of [tex]x[/tex] that are roots of this equation.

[tex]x^2 + 2x - 5 = 0[/tex]

A. [tex]x = -1 - 2\sqrt{6}[/tex]
B. [tex]x = -1 - \sqrt{6}[/tex]
C. [tex]x = -1 + 2\sqrt{6}[/tex]
D. [tex]x = -1 + \sqrt{6}[/tex]



Answer :

To find the roots of the quadratic equation [tex]\(x^2 + 2x - 5 = 0\)[/tex], we need to solve for [tex]\(x\)[/tex]. We can do this best by using the quadratic formula, which is given by:

[tex]\[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} \][/tex]

For the given quadratic equation [tex]\(x^2 + 2x - 5 = 0\)[/tex]:
- [tex]\(a = 1\)[/tex],
- [tex]\(b = 2\)[/tex],
- [tex]\(c = -5\)[/tex].

First, let's calculate the discriminant [tex]\(\Delta\)[/tex]:

[tex]\[ \Delta = b^2 - 4ac = (2)^2 - 4(1)(-5) = 4 + 20 = 24 \][/tex]

Next, we use the quadratic formula:

[tex]\[ x = \frac{-b \pm \sqrt{\Delta}}{2a} = \frac{-2 \pm \sqrt{24}}{2(1)} = \frac{-2 \pm 2\sqrt{6}}{2} \][/tex]

Simplifying the expression inside the fraction:

[tex]\[ x = \frac{-2 + 2\sqrt{6}}{2} \quad \text{and} \quad x = \frac{-2 - 2\sqrt{6}}{2} \][/tex]

This gives us:

[tex]\[ x = -1 + \sqrt{6} \quad \text{and} \quad x = -1 - \sqrt{6} \][/tex]

Thus, the two roots of the equation [tex]\(x^2 + 2x - 5 = 0\)[/tex] are:
[tex]\[ x = -1 + \sqrt{6} \quad (Option \, D) \quad \text{and} \quad x = -1 - \sqrt{6} \quad (Option \, B) \][/tex]

So the correct choices are:

[tex]\[ B. \quad x = -1 - \sqrt{6} \][/tex]

[tex]\[ D. \quad x = -1 + \sqrt{6} \][/tex]