Quadratic Equation Class 10 Notes: Chapter 4
Get the complete concepts covered in quadratic equations for class 10 Maths here. In this article, you will learn the concept of quadratic equations, standard form, nature of roots, methods for finding the solution for the given quadratic equations with more examples.
Introduction to Quadratic Equations
A polynomial of the form ax2+bx+c, where a,b and c are real numbers and a≠0 is called a quadratic polynomial.
For More Information On Quadratic Polynomials, Watch The Below Video.
When we equate a quadratic polynomial to a constant, we get a quadratic equation.
Any equation of the form p(x)=c, where p(x) is a polynomial of degree 2 and c is a constant, is a quadratic equation.
The standard form of a Quadratic Equation
The standard form of a quadratic equation is ax2+bx+c=0, where a,b and c are real numbers and a≠0.
‘a’ is the coefficient of x2. It is called the quadratic coefficient. ‘b’ is the coefficient of x. It is called the linear coefficient. ‘c’ is the constant term.
Solving QE by Factorisation
Roots of a Quadratic equation
The values of x for which a quadratic equation is satisfied are called the roots of the quadratic equation.
If α is a root of the quadratic equation ax2+bx+c=0, then aα2+bα+c=0.
A quadratic equation can have two distinct real roots, two equal roots or real roots may not exist.
Graphically, the roots of a quadratic equation are the points where the graph of the quadratic polynomial cuts the x-axis.
Consider the graph of a quadratic equation x2−4=0:
In the above figure, -2 and 2 are the roots of the quadratic equation x2−4=0
- If the graph of the quadratic polynomial cuts the x-axis at two distinct points, then it has real and distinct roots.
- If the graph of the quadratic polynomial touches the x-axis, then it has real and equal roots.
- If the graph of the quadratic polynomial does not cut or touch the x-axis then it does not have any real roots.
Solving a Quadratic Equation by Factorization method
Consider a quadratic equation 2x2−5x+3=0
This step is splitting the middle term
We split the middle term by finding two numbers (-2 and -3) such that their sum is equal to the coefficient of x and their product is equal to the product of the coefficient of x2 and the constant.
(-2) + (-3) = (-5)
And (-2) × (-3) = 6
In this step, we have expressed the quadratic polynomial as a product of its factors.
Thus, x = 1 and x =3/2 are the roots of the given quadratic equation.
This method of solving a quadratic equation is called the factorisation method.
For More Information On Solving a Quadratic Equation by Factorization method, Watch The Below Video.