We will discuss here about the polynomial equation and its roots.

If f(x) is a polynomial in x of degree ≥ 1 whose coefficients are real or complex numbers then f(x) = 0 is called its corresponding polynomial equation.

Examples of polynomial equation:

(i) 5x\(^{2}\) + 2 x - 7 is a quadratic polynomial and 5x\(^{2}\) + 2 x - 7 = 0 is its corresponding quadratic equation.

(ii) 2x\(^{3}\) + x\(^{2}\) + 5x - 3 is a cubic polynomial and 2x\(^{3}\) + x\(^{2}\) + 5x - 3 = 0 is its corresponding cubic equation.

(iii) x\(^{4}\) + x\(^{2}\) - 2x + 6 is a cubic polynomial and x\(^{4}\) + x\(^{2}\) - 2x + 6 = 0 is its corresponding cubic equation.

(iv) x\(^{5}\) + 2x\(^{4}\) + 2x\(^{3}\) + 4x\(^{2}\) + x + 2 is a cubic polynomial and x\(^{5}\) + 2x\(^{4}\) + 2x\(^{3}\) + 4x\(^{2}\) + x + = 0 is its corresponding equation.

If α be a value of x for which f(x) becomes zero, i.e., f(α) = 0, then α is said to be a root of the equation f(x) n= 0.

In other words,

α is called a root of the polynomial equation f(x) = 0 if f(α) = 0.

Examples of root of the polynomial equation:

(i) Let f(x) = 4x\(^{3}\) + 12x\(^{2}\) - 4x - 12. As 4(1)\(^{3}\) + 12(1)\(^{2}\) - 4(1) - 12 = 4 + 12 - 4 - 12= 0, i.e., f(1) = 0, f(x) = 0 has a root x = 1.

(ii) Let f(x) = x\(^{2}\) - 2x - 3. As (-1)\(^{2}\) - 2(-1) - 3 = 1 + 2 - 3 = 0, i.e., f(-1) = 0, f(x) = 0 has a root x = -1

(iii) Let f(x) = x\(^{4}\) + x\(^{3}\) – 2x\(^{2}\) + 4x - 24. As (2)\(^{4}\) + (2)\(^{3}\) - 2(2)\(^{2}\) + 4(2) - 24 = 16 + 8 – 8 +8 + 8 = 0, i.e., f(2) =0, f(x) has a root x = 2

(iv) Let f(x) = x\(^{3}\) + x\(^{2}\) - x - 1. As (1)\(^{3}\) + (1)\(^{2}\) – (1) – 1 = 1 + 1 - 1 - 1 = 0, i.e., f(1) = 0, f(x) = 0 has a root x = 1.

● **Factorization**

**Polynomial****Polynomial Equation and its Roots****Division Algorithm****Remainder Theorem****Problems on Remainder Theorem****Factors of a Polynomial****Worksheet on Remainder Theorem****Factor Theorem****Application of Factor Theorem**

**From Polynomial Equation and its Roots to HOME**

**Didn't find what you were looking for? Or want to know more information
about Math Only Math.
Use this Google Search to find what you need.**

## New! Comments

Have your say about what you just read! Leave me a comment in the box below. Ask a Question or Answer a Question.