Which of the following is not a quadratic equation?

• 2x(x + 4) -11 = x(x - 3) + 6
• 4x(x + 4) -11 = 5x(x - 3) + 5
• x(x + 2) -15 = x(x - 5) + 11
• 2x2 + 8x - 11 = 0