Question

Solve x2 - 8x = 20 by completing the square. Which is the solution set of the equation

Answer 1

Answer: D

Explanation:

basically how i remember to do this is asking myself what multiples to 20 and then what adds up to -8

Answer 2

x = 10 or x = -2

Explanation:

`{x}^(2) - 8x = 20 \\ {x}^(2) - 2 * x * 4 + {4}^(2) - {4}^(2) = 20 \\ {x}^(2) - 8x + 16 - 16 = 20 \\ {x}^(2) - 8x + 16 = 20 + 16 \\ {(x - 4)}^(2) = 36 \\ |x - 4| = √(36) \\ |x - 4| = 6 \\ x - 4 = + - 6 \\ x = 4 + - 6 \\ \\ x = 4 + 6 = 10 \\ or \\ x = 4 - 6 = - 2`