- i) An expression of the form a0xn + a1xn-1+....+ an = 0, where n is a positive integer and a0, a1,...,an belong to some number system F, is called a polynomial in the variable x over F.
- ii) The degree of polynomial is defined as the highest index of the variable x occurring in the polynomial.
ii) An equation is a statement of equality between two expressions which is not true for all values of the variable involved.
- If f(x)=0 is a polynomial equation and f(a)=0, then 'a' is a root of the polynomial equation.
If ax2 + bx + c = 0, a = 0, then
where a, b, c be any complex numbers.
- A quadratic equation has exactly two roots.
- For the quadratic equations, we have
Roots are real and distinctii) b2 - 4ac = 0
Roots are real and equaliii) b2 - 4ac < 0
Roots are imaginary and distinct
- If the roots of ax2 + bx + c = 0, a(¹ 0),b, c Î R, are a and b, then

- An expression in a, b is called a symmetric function of a, b if the expression is not affected by interchanging a and b.
- The quadratic equation with roots a and b is given by x2- Sx + P = 0 where S = a + b and P = ab.
