a² - b² = (a - b)(a + b)
(4х+1)^2=12y
(x+4)^2=3y |*4 4(x + 4)^2 = 12y
вычитаем второе из первого
(4x + 1)^2 - (2(x + 4))^2 = 12y - 12y
(4x + 1 - 2x - 8)(4x + 1 + 2x + 8) = 0
(2x - 7)(6x + 9) = 0
x = 7/2
(4*7/2 + 1)^2 = (14 + 1)^2 = 15^2 = 225 = 12y
y = 225/12
x = -9/6 = -3/2
(4*(-3/2) + 1)^2 = (-6 + 1)^2 = 25 = 12y
y = 25/12
(-3/2, 25/12) (7/2, 225/12)
