Respuesta :

Using the quadratic formula

The quadratic formula can help us solve for x in a quadratic equation:

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

We can use this when the given equation is organized in standard form: [tex]ax^2+bx+c=0[/tex]

Applying this to the problem

[tex]2x^2+5x-4=0[/tex]

First we can identify the values of a, b and c:

a = 2

b = 5

c = -4

Plug these values into the quadratic formula:

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

[tex]x=\dfrac{-5 \pm \sqrt{5^2-4(2)(-4)}}{2(2)}[/tex]

[tex]x=\dfrac{-5 \pm \sqrt{25+32}}{4}[/tex]

[tex]x=\dfrac{-5 \pm \sqrt{57}}{4}[/tex]

Answer

Therefore, the two possible values of x are:

[tex]x=\dfrac{-5 +\sqrt{57}}{4}[/tex]

[tex]x=\dfrac{-5 -\sqrt{57}}{4}[/tex]

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