Answer:
x = 5, -3
Step-by-step 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
