(2х - 1)² = 16
4х² - 4х + 1 = 16
4х² - 4х = 16 - 1
4х² - 4х = 15
4х² - 4х - 15 = 0
Д = 4² - 4 . -15 . 4
Д = 16 + 240 Д = 256
х₁,₂ = 4 ± 16 : 8
х₁ = (4 + 16) : 8 = 20 : 8 = =
х₂ = (4 - 16) : 8 = -12 : 8 = = -
(2х - 1)² = 16
4х² - 4х + 1 = 16
4х² - 4х = 16 - 1
4х² - 4х = 15
4х² - 4х - 15 = 0
Д = 4² - 4 . -15 . 4
Д = 16 + 240 Д = 256
х₁,₂ = 4 ± 16 : 8
х₁ = (4 + 16) : 8 = 20 : 8 = =
х₂ = (4 - 16) : 8 = -12 : 8 = = -