Defintion and Introduction to Quadratic Equations

Definition:

Any equation in the form of ax² + bx + c, where a != 0 is called a Quadratic
Equation. ('a != 0' means 'a is not equal to zero')



Alternatively,

If the highest exponent over any variable in an equation is 2, it is known as a
Quadratic Equation.

Or,  
Any equation formed by equating a quadratic expression to zero is a quadratic equation.

Examples of Quadratic Equations:

• 2x² + 2x + 1 is a quadratic equation in the variable 'x'
• 3y² + 3y + 1 is a quadratic equation in the variable 'y'
• 8x² + 16 = 37x is a quadratic equation in the variable 'x'
• x² = 1 is a quadratic equation in the variable 'x'
• x² - 1 = 0 is a quadratic equation in the variable 'x'
• a² = 0 is a quadratic equation in the variable 'a'