Algebra: Completing the Square

Complete the square for

x² - 14x + __

(type the missing value that goes in the blank)

The quadratic shown is going to be solved by completing the square, the first step is shown

Problem: x² + 6x = 5

Step 1: x² + 6x + ​ (a)   = ​ (b)  

What are the missing values?

• 9
• 14
• 6
• 5
• -6
• -9
• 3
• 8
• 12

The following quadratic is going to be solved by completing the square. Which choice shows Step 2?

Problem : x² + 12x = 13

Step 1 : x² + 12x + 36 = 49

Step 2 : ​ ?

What value of c would make this a perfect square trinomial?

x² +8x + c

• 4

• 16

• 64

• 8

What are the steps to solving this by completing the square?

a² + 10a + 21 = 0

• Take the square root of both sides of the equation

• Subtract 21 from both sides of the equation

• Rewrite the left hand side as a (binomial)²

• Add 25 to both sides of the equation

• Subtract 5 from both sides of the equation

Complete the square for

x² - 12x + ____

• 144

• 36

• - 36

• 24

Complete the square.

x² + 6x + ____

• 9

• 12

• 36

• - 9

x² - 18x + (a)   = (x -​ (b)   )²​

• 81
• 18
• 27
• 9
• 3
• 1
• 36