а) 16x^4 - 81 = (4x^2 + 9)(4x^2 - 9) = (4x^2 + 9)(2x + 3)(2x - 3)
б) x^2 - x - y^2 - y = (x^2 - y^2) - (x + y) = (x - y)(x + y) - (x + y) = (x + y)(x - y - 1)
а) 16x^4 - 81 = (4x^2 + 9)(4x^2 - 9) = (4x^2 + 9)(2x + 3)(2x - 3)
б) x^2 - x - y^2 - y = (x^2 - y^2) - (x + y) = (x - y)(x + y) - (x + y) = (x + y)(x - y - 1)