Question

4x2+16x+8=0 by completing the square

Answer 1

Answer:

Add  

8

to both sides of the equation.

2

x

2

+

16

x

=

8

Divide each term by  

2

and simplify.

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x

2

+

8

x

=

4

To create a trinomial square on the left side of the equation, find a value that is equal to the square of half of  

b

.

(

b

2

)

2

=

(

4

)

2

Add the term to each side of the equation.

x

2

+

8

x

+

(

4

)

2

=

4

+

(

4

)

2

Simplify the equation.

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x

2

+

8

x

+

16

=

20

Factor the perfect trinomial square into  

(

x

+

4

)

2

.

(

x

+

4

)

2

=

20

Solve the equation for  

x

.

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x

=

±

2

√

5

−

4

The result can be shown in multiple forms.

Exact Form:

x

=

±

2

√

5

−

4

Decimal Form:

x

=

0.47213595

…

,

−

8.47213595

…

Step-by-step explanation: