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Solve x2 + 12x = –20 by completing the square. Add (StartFraction b Over 2 EndFraction) squared to both sides of the equation. The value of (StartFraction b Over 2 EndFraction) squared in this equation is . Write the left side of the equation as a binomial squared. The left side of the equation becomes ( )2. Use the square root property of equality. Isolate the variable: x =

Respuesta :

Answer:

x=-2,x=-10

Step-by-step explanation:

x²+12x=-20

add both sides (12/2)^2 ,i.e.,36

x+2+12x+36=-20+36

(x+6)²=16=4²

x+6=±4

either x+6=4

x=4-6

x=-2

or x+6=-4

x=-4-6

x=-10

lhmarianateixeira

In this exercise we have to use the knowledge of equations to calculate the value that X can obtain, in this way we find that:

[tex]x=-2\\x=-10[/tex]

Given the initial equation as:

[tex]x^2+12x=-20[/tex]

We will have to add on both sides of the equation the value of 36, so we find that:

[tex]x^2+12x+36=-20+36\\(x+6)^2=16=4^2\\x+6=\±4[/tex]

As every quadratic equation we find two possible values ​​for X and we will have to test them, so:

  • The first value:

[tex]x+6=4\\x=4-6\\x=-2[/tex]

  • The second value:

[tex]x+6=-4\\x=-4-6\\x=-10[/tex]

See more about quadratic equations at brainly.com/question/4119784

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