[tex](2x+1)^2-(2x-4)(2x+4) < x+1\\4x^2+4x+1-(4x^2-16) < x+1\\4x^2+4x+1-4x^2+16 < x+1\\4x^2-4x^2+4x-x < 1-1-16\\3x < -16/:3\\x < -\frac{16}3[/tex]
