Question

Complete the Square
Solve by completing the square. Show ALL your work
1. x^2 – 8x + 5 = 0
2. x^2 + 12x + 4 = 0
3. x^2+ 18x + 90 = 0
4. –2x^2 – 12x – 9 = 0
5. 4x^2 + 8x – 9 = 0

Answer 1

${x}^{2} - 8x + 5 = 0 \\ {x}^{2} -8x + 16 - 16 + 5 = 0 \\ {(x - 4)}^{2} - 11 = 0 \\ (x - 4 - \sqrt{11} )(x - 4 + \sqrt{11} ) = 0 \\ x = 4 + \sqrt{11} \: \: or \: \: \: 4 - \sqrt{11}$