Algebraic Identities Expressions Polynomials Class 9 ICSE CBSE Ex. 2.5 Q1, NCERT Solution

Use suitable identities to find the following products:

(i) (x + 4) (x + 10)  (ii) (x + 8) (x – 10)
(iii) (3x + 4) (3x – 5) (iv) (y2 + 3/2) (y2 –3/2)
(v) (3 – 2x) (3 + 2x)

In all these videos on Polynomials from class 9th chapter 2 I have always focused on explaining the basics and then solving the questions. My way of solving question will always refer back to the basics explained previously so that students can make the connect between basics and application of them.
Let’s now start about the Polynomials:
Polynomials are the back bone of Algebra or better to say the start of algebra. We must need understand what is a polynomial to understand the algebra. In this chapter of polynomials we will will firs of all understand how to identify polynomials. What are polynomials and what is not polynomials. It is sometimes very difficult to identify them and that’s the place we make most of the mistakes. In my basic videos I have explained very clearly what is a polynomial and what is not a polynomial.

What is a Polynomial (Basics)
Variables, variables with constants, algebraic expression or just a constant
Condition: Variable, algebraic expression should have +ve integer as power
x, y, z, 2x, 5y, 4x2, (8x3 + 5z) , (2xy + 3z – xz)
2, 0, 10…..(all the real numbers are polynomials)

What is a NO Polynomial (Basics)
x-1 , 5y3/2 , 3y-7
Powers should be only non negative integer

Algebraic Identities
Identity 1: {(x+y)}^2 = x^2 + 2xy + y^2
Identity 2: {(x-y)}^2 = x^2 - 2xy + y^2
Identity 3: (x^2 - y^2) = (x + y) (x- y)
Identity 4: (x + a) (x + b) = x^2 + (a + b)x + ab
Identity 5: {(x+y+z)}^2 = x^2 + y^2 + z^2 + 2xy + 2yz + 2zx
Identity 6: \ {(x+y)}^3 = x^3 + y^3 + 3xy (x + y)
Identity 7: \ {(x-y)}^3 = x^3 - y^3 - 3xy (x - y)
Identity 8: x^3 + y^3 + z^3 - 3xyz = (x + y + z) (x^2 + y^2 + z^2 - xy – yz – zx)

We will learn about:

Zeros of a polynomial
Remainder theorem
Factorisation of a polynomial
Algebraic identities
Cubic polynomials and their factorization
Questions from all the topics and exercises.

As per the syllabus, you will learn all the topics in my Polynomial Chapter Videos:

Please use this link for the YouTube playlist of Polynomials Class 9th:

Class 9 - Geometry - Number System - Algebra Practice Questions

Quadrilaterals Class 9 NCERT CBSE Solutions

Triangles Class 9 NCERT CBSE Solutions

Surface Areas and Volumes Class 9

Heron's Formula Class 9 NCERT CBSE Solutions

Circle Class 9 NCERT CBSE Solutions

Areas of Parallelograms and Triangles Class 9

Lines and Angles Class 9

Linear Equations in Two Variables Class 9

Coordinate Geometry Class 9

Polynomials Class 9

Number Systems Class 9

Mathsphy provides unconventional and a better way of learning maths. It saves time and gives you ease of learning anytime anywhere at your convenience. It has more than 1000 videos for 9th , 10th and 11th grade students explaining topic concepts and then solving all the questions in a very professional language giving you the experience of personalized tutoring.

Class 9 I have: Number System, Polynomials, Coordinate Geometry, Linear Equations in Two Variable, Lines and Angles, Triangles, Quadrilaterals, Circle, Areas of Parallelograms and Triangles, Herons's Formula, Surface Areas and Volumes, Statistics and Probability.

Find us on youtube

Find us on Facebook:
Contact:
Abhishek Agarwaal
[phone]

[nandiniachari]

Sir please can you help me in this question (4x+5)(3x-4)

[nithun.mnithun.m]

your teaching method is good but your writing is very fast due to that unable to copy down it

[rikhavpatel]

Thank you sir it helped me very much as i was finding difficulty in my school's method....