Which are the solutions of x2 = 19x + 1?

StartFraction 19 minus StartRoot 19 EndRoot Over 2 EndFraction comma StartFraction 19 + StartRoot 19 EndRoot Over 2 EndFraction
StartFraction 19 minus StartRoot 365 EndRoot Over 2 EndFraction comma StartFraction 19 + StartRoot 365 EndRoot Over 2 EndFraction
StartFraction negative 19 minus StartRoot 19 EndRoot Over 2 EndFraction comma StartFraction negative 19 + StartRoot 19 EndRoot Over 2 EndFraction
StartFraction negative 19 minus StartRoot 365 EndRoot Over 2 EndFraction comma StartFraction negative 19 + StartRoot 365 EndRoot Over 2 EndFraction

Respuesta :

Answer:

[tex](\frac{19-\sqrt{365}} {2},\frac{19+\sqrt{365}} {2})[/tex]

Step-by-step explanation:

we have

[tex]x^2=19x+1[/tex]

we know that

The formula to solve a quadratic equation of the form

[tex]ax^{2} +bx+c=0[/tex]

is equal to

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

in this problem we have

[tex]-x^{2}-19x-1=0[/tex]  

so

[tex]a=1\\b=-19\\c=-1[/tex]

substitute in the formula

[tex]x=\frac{-(-19)\pm\sqrt{-19^{2}-4(1)(-1)}} {2(1)}[/tex]

[tex]x=\frac{19\pm\sqrt{365}} {2}[/tex]

[tex]x=\frac{19+\sqrt{365}} {2}[/tex]

[tex]x=\frac{19-\sqrt{365}} {2}[/tex]

[tex](\frac{19-\sqrt{365}} {2},\frac{19+\sqrt{365}} {2})[/tex]

therefore

StartFraction 19 minus StartRoot 365 EndRoot Over 2 EndFraction comma StartFraction 19 + StartRoot 365 EndRoot Over 2 EndFraction

Answer:

The answer is B

Step-by-step explanation:

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