# NCERT Solutions for Class 8 Maths Chapter 9 Exercise 9.1

CBSE NCERT Solutions for Class 8 Maths Chapter 9 Exercise 9.1 (Ex. 9.1) Algebraic Expressions and Identities in Hindi Medium and English Medium free. All the contents are updated according to CBSE syllabus 2021-2022.

PDF and Videos are given here to explain all the question answers with solution of exercise 9.1 of grade 8 mathematics. Algebraic expression is one of the important chapters of class 8 mathematics.

## Class 8 Maths Chapter 9 Exercise 9.1 Solution

 Class: 8 Mathematics Chapter: 9 Algebraic Expressions and Identities Exercise: 9.1 NCERT Solutions in Hindi and English

### Class 8 Maths Chapter 9 Exercise 9.1 Solution in Videos

Class 8 Maths Chapter 9 Exercise 9.1 Solution
Class 8 Maths Chapter 9 Exercise 9.1 Explanation

#### Algebraic Expressions

algebraic expression is a combination of variables and constant terms, which are connected by mathematical operations of addition, subtraction, multiplication and division”. Consider 2x + 3 and 5a – 2.
(i) 2 and 2 are constants and x is a variable. 2x + 3 is an algebraic expression consisting of two terms 2x and 3 connected together with the sign of addition.
(ii) 5a – 2 consists of two terms 5a and 2, connected together with the sign of subtraction. 5 and –2 are constants whereas a is a variable.

##### Monomial:

An algebraic expression which has only one term is called a monomial. 2 2 e.g., 2x, 3x y, –5xy etc.

##### Binomial:

An algebraic expression which has two terms is called a binomial. e.g., 2x + 3, 5x(3/2), 7x + ½ etc.

##### Trinomial:

Any algebraic expression, which has one or more terms is called a trinomial.
5x + y – 6, x² + 5x – 6, x³ – xyz + 7 etc.

##### Polynomial:

Any algebraic expression, which has one or more terms is called a polynomial.

##### Like and Unlike Terms:

In a given expression, the terms having the same literal factors are called like terms, otherwise they are called unlike terms. Consider the algebraic expressions:
(a) 3×2 – 7x + 5×2 + 2, (b) 4×2 – y2 + 3×2 + 5y2 + z, (c) 2xy2 – 3×2 + 7xy
(a) 3×2 and 5×2 are like terms.
(b) 4×2 and 3×2 are like terms, – y2 and 5y2 are like terms.
(c) There are three terms 2xy2, –3×2 and 7xy and they are all unlike terms as they have different variables viz. xy2, x2, xy.

##### Add: 6a + 8b – 5c, 2b + c – 4a and a – 3b – 2c.

Writing the terms of the given expressions in the same order in form of rows with like terms below each other and adding column wise, we get:
6a + 8b – 5c
– (4a + 2b + c)
+ a – 3b – 2c
= 3a + 7b 6c

##### What are algebraic expressions Class 8?

Algebraic expressions are expressions formed from the variables and the constants. A variable can take any value. The value of an expression changes with the value chosen for variables it contains. A number line has infinite number of points.

##### How do you simplify expressions?

To simplify any algebraic expression, the following are the basic rules and steps:
(i) Remove any grouping symbol such as brackets and parentheses by multiplying factors.
(ii) Use the exponent rule to remove grouping if the terms are containing exponents.
(iii) Combine the like terms by addition or subtraction.
(iv) Combine the constants.

##### Add: 5x² + 3x – 8, 4x + 7 – 2x² and 6 – 5x + 4x².

Writing the given expressions in descending powers of x in the form of rows with like terms below each other and adding column wise, we get:
5x² + 3x – 8
– 2x² + 4x + 7
4x² – 5x + 6
= 7x² + 2x + 5    