Question

Show all steps when completing the square to solve 2x^2 - 4x - 5 = 25

Answer 1

x = 5, -3

Explanation:

2x² - 4x - 5 = 25

add 5 to each side

2x² - 4x = 30

factor out the 2

2(x² - 2x) = 30

divide both sides by 2

x² - 2x = 15

divide b by 2, square it -- (b/2)², and add it to both sides

-2/2 = -1 → -1² = 1

x² - 2x + 1 = 15 + 1

factor the expression on the left -- this will be [x - (b/2)]²

(x - 1)² = 16

find the square root of both sides

x - 1 = ±4

add 1 to both sides

x = 4 + 1

x = -4 + 1

solve

x = 5, -3