Respuesta :

x = 20
First, you move the 40 to the other side.
-2x=-40
Then, you divided -40 by -2.
x= -40/-2
x= 20
x is 20 because the negatives cancel out making it positive.

Answer:

[tex]x=+2\sqrt{10}[/tex]

[tex]x=-2\sqrt{10}[/tex]

Step-by-step explanation:

[tex]40-x^2=0[/tex]

To solve for x , subtract 40 from both sides

[tex]-40+40-x^2=0-40[/tex]

[tex]-x^2=-40[/tex]

Divide both sides by -1

[tex]x^2= 40[/tex]

Take square root on both sides

[tex]\sqrt{x^2} =\sqrt{40}[/tex]

[tex]x=+-2\sqrt{10}[/tex]

The values of x are

[tex]x=+2\sqrt{10}[/tex]

[tex]x=-2\sqrt{10}[/tex]