Respuesta :

carlosego
x ^ 2 - 18 = 0
 For this case, the first thing you should do is rewrite the expression:
 x ^ 2 - 18 = 0
 x ^ 2 = 18
 The solutions for this case are:
 x1 = root (18)
 x2 = -raiz (18)
 Therefore the answer is:
 2 solutions of real numbers.
 Answer:
 2

Answer:

The number of real roots is 2.

Step-by-step explanation:

Given,

[tex]x^2 -18 = 0[/tex]

We will find the number of roots by Descartes' rule of signs.

Let,

[tex]f(x)=x^2-18[/tex]

Since,

[tex]f(x) = + x^2 - 18[/tex]

That is, the change in the sign shows, the given polynomial has one positive real root.

Now, by putting x = - x,

[tex]f(-x)=(-x)^2- 18 = x^2 - 18[/tex]

[tex]\implies f(-x) = + x^2 - 18[/tex]

That is, the change in the sign shows, the given polynomial has one negative real root.

We know that, given polynomial has degree 2,

⇒ It only has 2 roots one is positive real and another is negative real,

⇒ f(x) having 2 real roots.

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