QUADRATIC EQUATIONS

CONTENT

1. Revision of linear and quadratic expressions
2. Solution of quadratic expression of the form ab = 0, a = 0 or b = 0
3. Formation of quadratic equation with given roots

REVISION OF LINEAR AND QUADRATIC EXPRESSIONS

Any expression in which highest power of the unknown is 1 is called a linear expression. Some examples of linear expressions are: (a) x + 1   (b) 2y + 3   (c) p = −1/2

In general, linear expressions are expressions of the form ax + b, where a & b are constants and x is a variable.

A quadratic expression is that whose highest power of the unknown is 2. Examples are:

(a) x² + 3x

(b) 2x² − 6x + 10

Factorization of quadratic expressions:

Examples:  (i) Factorize the following quadratic expressions

(a) x² + 4x

(b) 2x² − 8x

Solution:

(a) x² + 4x

x is a common factor of the terms x² and 4x.