Completing the Square

When factoring
x² - 4x + 4 = 20,
what goes in the blank?
(x - __ )² = 20

• 4
• 2
• 8
• 20

Complete the Square
x² + 6x = 5

• (x + 3)² = 5
• (x + 6)² = 9
• (x + 3)² = 14
• (x + 6)² = 14

Complete the square.
x² + 14x + ____

• x² + 14x - 196
• x² + 14x + 49
• x² + 14x - 49
• x² + 14x + 196

Solve by completing the square:
k² − 12k + 23 = 0

• {6 + √13, 6 - √13}
• {-6 + √13, -6 - √13}
• {6 + √59, 6 - √59}
• {-6 + √59, -6 - √59}

Solve
 3x² + 5x - 12 = 0

• x = -4/3, x = 3
• x = 4/3, x = -3
• x = -1, x = 4
• x = 1, x = -4

• -4

• 4

• 8

• 16

Answer explanation

In this standard-form quadratic, a = 1 and b = 8.  Therefore,  $c=\left(\frac{8}{2}\right)^2=16.$  

• -121

• 121

• 11

• -11