Students will come to know that a polynomial of the form ax2+bx+c, where a, b and c are real numbers and a≠0 is called a quadratic polynomial.
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 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.
Some important topics to study in this chapter are as follows:
- Factorisation method
- Completing the square method
- Nature of Roots
Students can view and download the solutions from the link given below.
NCERT Solutions for Chapter 4: Quadratic Equations
Also Check
Chapter 1: Real Numbers
Chapter 2: Polynomials
Chapter 3: Pair of Linear Equations in Two Variables
Chapter 5: Arithmetic Progression
Chapter 6: Triangles
Chapter 7: Coordinate Geometry
Chapter 8: Introduction to Trigonometry
Chapter 9: Some Applications of Trigonometry
Chapter 10: Circle
Chapter 11: Constructions
Chapter 12: Areas Related to Circles
Chapter 13: Surface Areas and Volume
Chapter 14: Statistics
Chapter 15: Probability
Check out Frequently Asked Questions (FAQs) for Chapter 4: Quadratic Equations
The quadratic equation has degree
The cubic equation has degree
A bi-quadratic equation has degree
A natural number, when increased by 12, equals 160 times its reciprocal. Find the number.
Let the number be x
Then according to question,
x + 12 = 160/x
x2 + 12x – 160 = 0
x2 + 20x – 8x – 160 = 0
(x + 20) (x – 8) = 0
x = -20, 8
Since the number is natural, so we consider only positive value.
Rohini had scored 10 more marks in her mathematics test out of 30 marks, 9 times these marks would have been the square of her actual marks. How many marks did she get in the test?
Let her actual marks be x
Therefore,
9 (x + 10) = x2
⇒x2 – 9x – 90 = 0
⇒x2 – 15x + 6x – 90 = 0
⇒x(x – 15) + 6 (x – 15) = 0
⇒(x + 6) (x – 15) = 0
Therefore x = – 6 or x =15
Since x is the marks obtained, x ≠ – 6. Therefore, x = 15.