Completing the Square & Square Root to Solve

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

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

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 by completing the square.
y² + 10y = -9

• 1 and -12
• -1 and -9
• 1 and -9
• 1 and -1

Solve by completing the square.
x² +12x = 5

• X = 6 + √41 or  6 − √41
• X= 35 or 47
• X = −6 + √41 or  −6 − √41
• X = √35 or √47

Solve by taking the Square Root:

16a² - 9 = 0

• a = ± ³/₄

• a = ± ⁴/₃

• a = ± ⁹/₁₆

• a = ± ¹⁶/₉

Solve by taking the Square Root:

4m² - 100 = 0

• m = ± 25

• m = 96

• m = ± 5

• m = -96

Solve for x by taking the Square Root:

(x+6)² = 49

• x = 7 and 12

• x = ±7

• x = 1 and -13

• x = 43 and -55

Solve the equation using square roots:

x² = 121

• x = 60.5

• x = ± 11

• x = ± 12

• x= 11