Verified answer

a) 2x² - xy = x(2x - y)

б) 36c² - 25 = (6c)² - 5² = (6c - 5)(6c + 5)

в) 3x + 3y + c(x + y) = (3x + 3y) + c(x + y) = 3(x + y) + c(x + y) = (x + y)(3 + c)