What is the completely factored form of f(x)=x3+5x2+4x−6?

f(x)=(x−3)(x−(−1+i3√))(x−(−1−i3√))

f(x)=(x+3)(x−(−1+i3√))(x−(−1−i3√))

f(x)=(x+3)(x−(−1+3√))(x−(−1−3√))

f(x)=(x−3)(x−(−1+3√))(x−(−1−3√))

Respuesta :

[tex]f(x)=x^3+5x^2+4x-6[/tex]
[tex]f(-3)=(-3)^3+5(-3)^2+4(-3)-6=0\implies x+3\text{ is a factor of }f(x)[/tex]

Synthetic division yields

-3  |  1   5   4   -6
.    |      -3  -6    6
- - - - - - - - - - - - -
.    |  1   2  -2    0

which translates to

[tex]\dfrac{x^3+5x^2+4x-6}{x+3}=x^2+2x-2[/tex]

with remainder 0. Now by the quadratic formula,

[tex]x^2+2x-2=0\implies x=\dfrac{-2\pm\sqrt{2^2-4(1)(-2)}}2=-1\pm\sqrt3[/tex]

and so

[tex]f(x)=x^3+5x^2+4x-6=(x+3)(x-(-1+\sqrt3))(x-(-1-\sqrt3))[/tex]

The factored type is the product of constants and two-dimensional terms, that is the root of a function as well as the graph's x-intercepts, and the further calculation can be defined as follows:

Given:

[tex]\bold{f(x)=x^3+5x^2+4x-6}[/tex]

To find:

factored form=?

Solution:

[tex]\bold{f(x)=x^3+5x^2+4x-6}[/tex]

putting the value x=-1,-2,-3...... to find the function value 0.

[tex]\to \bold{f(-1)=-1^3+5(-1)^2+4(-1)-6}\\\\[/tex]

              [tex]\bold{=-1+5\times 1+4 \times (-1)-6}\\\\ \bold{= -1+5-4-6} \\\\ \bold{=-6}\\\\[/tex]

[tex]\to \bold{f(-2)=-2^3+5(-2)^2+4(-2)-6}[/tex]

              [tex]\bold{=-8+5\times 4+4 \times(- 2)-6}\\\\\bold{= -8+20-8-6}\\\\\bold{=-2}\\\\[/tex]

[tex]\to \bold{f(-3)=-3^3+5(-3)^2+4(-3)-6}[/tex]

              [tex]\bold{=-27+5\times 9+4 \times(- 3)-6}\\\\\bold{= -27+45-12-6}\\\\\bold{=0}\\\\[/tex]

Therefore, [tex]\bold{(x+3)}[/tex] is the factor of the function.

Let [tex]\bold{(x+3)}[/tex] divide by the function:

[tex]\to \bold{\frac{x^3+5x^2+4x-6}{(x+3)}= x^2+2x-2}[/tex]

compare the value [tex]\bold{x^2+2x-2}[/tex] by the standard equation [tex]\bold{ax^2+bx+c=0}[/tex] so,

[tex]\bold{a=1}\\\\\bold{b=2}\\\\\bold{c=-2}\\\\[/tex]

Putting value into the quadratic equation formula:

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

[tex]\bold{x=\frac{-(2) \pm \sqrt{(2)^2-4\times 1 \times -2}}{2\times 1}}\\\\\bold{x=\frac{-2 \pm \sqrt{4+8}}{2}}\\\\\bold{x=\frac{-2 \pm \sqrt{12}}{2}}\\\\\bold{x=\frac{-2 \pm 2\sqrt{3}}{2}}\\\\\bold{x=\frac{2(-1 \pm \sqrt{3})}{2}}\\\\\bold{x=(-1 \pm \sqrt{3})}\\\\\bold{x=(-1 + \sqrt{3}) (-1 -\sqrt{3})}\\\\[/tex]

Adding the factor value that is [tex]\bold{(x+3)}[/tex] so, the value is "[tex]\bold{(x+3)(-1+\sqrt{3})(-1-\sqrt{3}) }[/tex]"

So, the final answer is "[tex]\bold{f(x)=(x+3)(x-(-1+\sqrt{3}))(x-(-1-\sqrt{3}))}[/tex]"

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