x^2 = (3x+1)^2x^2 - (3x+1)^2 = 0[x + (3x+1)] * [x - (3x+1)] = 0(4x + 1) * (-2x - 1) = 0(4x + 1) * (2x + 1) = 04x + 1 = 0 或 2x + 1 = 0x = -1/4 或 x = -1/2