Solving a polynomial equation or inequality write polynomial into product of polynomials which can not factored that is 1. linear expressions e.g. x, (x+3), (x-5), (2x-1), 2. quadratic expressions with Delta * 0 e.g. (x^2+9), (x^2+7), (x^2+2x+8). From the factored polynomial is easy to find roots. Examples: x^3-x^2-17x-15 = (x-5)(x+3)(x+1). Roots: x_1 = 5, x_2 = -3, x_3 = -1. x^4+6x^3+16x^2+32x = x(x+4)(x^2+2x+8) Roots: x_1 = 0, x_2 = -4.