- The general form of a quadratic equation is ax^2 + bx + c = 0. There are various methods to solve quadratic equations like factorizing, completing the square, or using the quadratic formula. - The discriminant (D) determines the nature of the roots - if D>0 then roots are real and distinct, if D=0 then roots are real and equal, if D<0 then roots are imaginary. - Several properties are described regarding the relationship between the signs of coefficients a, b, c and the nature of the roots. - Example problems are given to illustrate solving quadratic equations and proving properties about roots.