Respuesta :

Given equation to us is [tex] x^2+4=8x+5[/tex]

And we need to find out the solutions to the given equation. We can rewrite the equation as ,

[tex]\longrightarrow x^2+4-8x-5=0 [/tex]

Simplify,

[tex]\longrightarrow x^2-8x-1=0[/tex]

Now this equation is in standard form of quadratic equation which is [tex]ax^2+bx+c=0[/tex]

With respect to the standard form ,

  • [tex] a =1[/tex]
  • [tex] b =-8[/tex]
  • [tex] c =-1[/tex]

Now we may use the quadratic formula for finding the roots as ,

Quadratic formula:-

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

So that,

[tex]\longrightarrow x =\dfrac{-(-8)\pm\sqrt{-8^2-4(1)(-1)}}{2(1)}\\[/tex]

[tex]\longrightarrow x =\dfrac{8\pm\sqrt{64+4}}{2}\\[/tex]

[tex]\longrightarrow x =\dfrac{8\pm \sqrt{68}}{2}\\ [/tex]

[tex]\longrightarrow x =\dfrac{8\pm 2\sqrt{17}}{2}\\ [/tex]

[tex]\longrightarrow\underline{\underline{ x = 4\pm \sqrt{17}}} [/tex]

And we are done!