If f ( x ) = x 3 + 2 x 2 − 5 x − 6 f(x)=x 3 +2x 2 −5x−6 and x − 2 x−2 is a factor of f ( x ) f(x), then find all of the zeros of f ( x ) f(x) algebraically.

Respuesta :

Answer:

The factors of the given function f(x) are (x-2),(x+1) and (x+3)

and zeros are 2,-1,-3

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

Step-by-step explanation:

Given function f is defined by [tex]f(x)=x^3+2x^2-5x-6[/tex]

To find the zeros of the given function f(x) :

First equate f(x)=0

That is [tex]f(x)=x^3+2x^2-5x-6=0[/tex]

Given that x-2 is a factor of f(x)

x-2=0

x=2

Put x=2 in [tex]f(x)=x^3+2x^2-5x-6[/tex]

[tex]f(2)=2^3+2(2)^2-5(2)-6[/tex]

[tex]=8+8-10-6[/tex]

Therefore f(2)=0 verified that x-2 is a factor

Put x=-1 in [tex]f(x)=x^3+2x^2-5x-6[/tex] we get

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

[tex]=-1+2+5-6[/tex]

[tex]=-7+7[/tex]

Therefore f(-1)=0

Therefore x+1 is a factor of f(x) and x+1=0

x=-1 is a zero of f(x)

Put x=-3 in [tex]f(x)=x^3+2x^2-5x-6[/tex] we get

[tex]f(-3)=(-3)^3+2(-3)^2-5(-3)-6[/tex]

[tex]=-27+2(9)+15-6[/tex]

[tex]=-27+18+9[/tex]

Therefore f(-3)=0

Therefore x+3 is a factor of f(x) and x+3=0

x=-3 is a zero of f(x)

Therefore the factors are (x-2),(x+1) and (x+3)

and zeros are 2,-1,-3

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