(2x - 1)² = 4x² - 4x + 1
(4b + 5c)(4b - 5c) = 16b² - 25c²
(5 - x)² - x(2,5 + c) = 0
25 - 10x + x² - 2,5x - cx = 0
x² - 12,5x - cx + 25
(2x - 1)² = 4x² - 4x + 1
(4b + 5c)(4b - 5c) = 16b² - 25c²
(5 - x)² - x(2,5 + c) = 0
25 - 10x + x² - 2,5x - cx = 0
x² - 12,5x - cx + 25