Solving Quadratics by Completing the Square & Quadratic Formula

Solve by completing the square: $x^2-4x+18=0$  

•  $x=-2\pm i\sqrt{14}$  

•  $x=-2\pm\sqrt{14}$  

•  $x=2\pm i\sqrt{14}$  

•  $x=2\pm\sqrt{14}$  

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.4

CCSS.HSA.SSE.A.2

CCSS.HSA.SSE.B.3

Solve $x^2+x=-1$  using the quadratic formula.

•  $x=-\frac{1}{2}\pm\frac{\sqrt{3}}{2}i$  

•  $x=-\frac{1}{2}\pm\frac{\sqrt{5}}{2}i$  

•  $x=\frac{1}{2}\pm\frac{\sqrt{3}}{2}i$  

•  $x=\frac{1}{2}\pm\frac{\sqrt{5}}{2}i$  

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.4

Use completing the square method to find the solutions of the equation  $x^2=23+2x$ . 

•  $x=-1\pm2\sqrt{6}$  

•  $x=1\pm2\sqrt{6}$  

•  $x=-1\pm\sqrt{22}$  

•  $x=1\pm\sqrt{22}$  

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.4

What is this formula?

• This is the speed of light formula.
• This is the quadratic formula.
• This is the zero product property.
• This is scary.

Tags

CCSS.HSA.REI.B.4

What do you do to the b value to correctly complete the square?

• square it
• divide it by 2 and square the result
• divide it by 2 and take the square root of the result
• divide it by 2 only

Tags

CCSS.HSA.SSE.A.2

CCSS.HSA.SSE.B.3

What is the first step to solving THIS equation by completing the square?
a² + 10a + 21 = 0

• Set the equation equal to zero
• Divide 10 by 2 and add the result to both sides
• Add a² and 10a together
• Subtract the 21

Tags

CCSS.HSA.REI.A.1

CCSS.HSA.REI.B.4

When factoring

x² - 4x + 4 = 20,

what goes in the blank?

(x - __ )² = 20

• 4

• 2

• 8

• 16

Tags

CCSS.HSA.REI.B.4

CCSS.HSA.SSE.A.2

CCSS.HSA.SSE.B.3

Complete the square for
x² + 12x + ____

• x² + 12x + 144
• x² + 12x + 36
• x² + 12x - 36
• x² + +12x - 144

Tags

CCSS.HSA.SSE.A.2

CCSS.HSA.SSE.B.3

When do you use the plus or minus symbol?
±

• After taking the square root of both sides
• After adding the square to both sides
• After taking half of b
• After setting the equation equal to zero

Tags

CCSS.HSA.REI.A.2

CCSS.HSA.REI.B.4

Find the value of c that makes x² + 16x + c a perfect square.

• -64

• 64

• 8

• 16

Tags

CCSS.HSA.REI.B.4

CCSS.HSA.SSE.A.2

CCSS.HSA.SSE.B.3