Respuesta :

Answer:

x² - x - 2 = 0

Step-by-step explanation:

plotting the graph of x and y,we have that the root of the equation is -1 or 2

x = -1 or 2

the eqn therefore is;

x² - (sum of the root)x + (product of the root) =. 0

x² - (-1+2)x + (-1*2) = 0

x² - x - 2 = 0

Applying the Factor Theorem, it is found that the quadratic function is:

[tex]p(x) = x^2 - x - 2[/tex]

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The Factor Theorem states that if a polynomial [tex]p(x)[/tex] has roots [tex]x_1, x_2, ..., x_n[/tex], it is described by the following equation:

[tex]p(x) = a(x - x_1)(x - x_2)...(x - x_n)[/tex]

In which a is the leading coefficient.

  • For this quadratic function, the roots are [tex]x_1 = -1, x_2 = 2[/tex], as [tex]y(-1) = y(2) = 0[/tex], thus:

[tex]p(x) = a(x - (-1))(x - 2)[/tex]

[tex]p(x) = a(x + 1)(x - 2)[/tex]

[tex]p(x) = a(x^2 - x - 2)[/tex]

When x = 0, p(x) = -2, and we use this to find a.

[tex]p(x) = a(x^2 - x - 2)[/tex]

[tex]-2 = a(0^2 - 0 - 2)[/tex]

[tex]2a = 2[/tex]

[tex]a = \frac{2}{2}[/tex]

[tex]a = 1[/tex]

Thus, the quadratic function is:

[tex]p(x) = x^2 - x - 2[/tex]

A similar problem is given at https://brainly.com/question/24380382