Completing The Square

Completing

The Square

Miss Sato

​Completing

the

Square

​Completing the Square

Fill in the Blanks

What number should replace the . . . ?

$x^2+4x-12=0$  

$x^2+4x=12$  

$x^2+4x+\ldots\ =12\ +\ldots$  

Multiple Choice

What should the next step be?

$$x^2+4x-12=0$$  

$$x^2+4x=12$$  

$$x^2+4x+4\ =12\ +4$$  

$$\left(x+2\right)\left(x+2\right)=16$$  

$$\left(x+2\right)^2=16$$  

• Take the square root

• Subtract 2 from both sides

• Expand (x+2)(x+2)

• Move 16 back to the left side and set equation = 0

Fill in the Blanks

Solve for x.

$x^2+4x-12=0$  

$x^2+4x=12$  

$x^2+4x+4\ =12\ +4$  

$\left(x+2\right)\left(x+2\right)=16$  

$\left(x+2\right)^2=16$

$\sqrt[]{\left(x+2\right)^2}=\ \pm\sqrt[]{16}$  

$x+2=\pm4$  

( Answer with no spaces: x={#,#} )

​Completing the Square

​****If 'a' is not equal to 1,

​then divide everything by 'a.'****

​

​Then follow the steps for completing the steps.

​

​Watch the video to the right.

Multiple Choice

Is a=1 in the following equation?

 

$$5x^2-10x-15=0$$  

• Yes

• No

Multiple Select

After dividing out 'a' which equation is correct?

$$5x^2-10x-15=0$$  

***There are two correct answers***

• $$x^2-10x-3=0$$  

• $$x^2-2x-3=0$$  

• $$x^2-2x=3$$  

• $$x^2+2x+3=0$$  

Fill in the Blanks

Given the following equation

$5x^2-10x-15=0$  

$x^2-2x=3$  

Solve for x by completing the square.

(Type Answer as x={#,#} )

See You In Class :)​

Study Your Notes!​