CBSE Class 7 Maths Algebraic Expressions NCERT Solutions
This chapter provides a foundational understanding of algebraic expressions for CBSE Class 7 Maths students. The NCERT Solutions cover key concepts such as identifying terms, coefficients, and factors within algebraic expressions. Students will learn to distinguish between monomials, binomials, and trinomials, and to correctly classify expressions based on the number of terms. The solutions also explain how to find like terms and work with coefficients. These detailed explanations and step-by-step solutions are designed to help students grasp the fundamental principles of algebra, making them well-prepared for future mathematical studies and examinations.
Quick info
| Board | CBSE |
|---|---|
| Class | Class 7 |
| Subject | Maths Exemplar |
| Session | 2026 |
| Language | English |
| Type | NCERT Solutions |
| Chapter | Chapter 10 |
Chapter summary
Chapter 10, Algebraic Expressions, focuses on introducing students to the basic building blocks of algebra. The NCERT Solutions cover the identification of terms, coefficients, and factors in various expressions. It clarifies the definitions of monomials, binomials, and trinomials, and provides practice in distinguishing between them. The exercises also involve recognizing like terms and understanding the concept of coefficients. This chapter lays the groundwork for more complex algebraic manipulations.
Learning outcomes
- Understand the definitions of monomial, binomial, and trinomial.
- Identify the terms and coefficients in an algebraic expression.
- Determine the factors of terms in an algebraic expression.
- Distinguish between like and unlike terms.
- Classify algebraic expressions based on the number of terms.
Topics covered
Paper topics
- Algebraic Expressions
- Terms
- Coefficients
- Factors
- Monomial
- Binomial
- Trinomial
- Like Terms
- Unlike Terms
- Identifying Terms
- Identifying Coefficients
- Identifying Factors
Important topics
- Definition of Algebraic Expressions
- Identifying Terms and Coefficients
- Factors of Terms
- Like and Unlike Terms
- Classification of Expressions (Monomial, Binomial, Trinomial)
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Questions and Solutions
Question 1
(a) monomial
(b) binomial
(c) trinomial
(d) All of these
The correct option is (c) trinomial.
An algebraic expression is classified based on the number of terms it contains:
- An expression with one term is called a monomial.
- An expression with two terms is called a binomial.
- An expression with three terms is called a trinomial.
Therefore, an algebraic expression containing three terms is called a trinomial.
Question 2
(a) 2
(b) 3
(c) 4
(d) 5
The correct option is (c) 4.
The given expression is . Terms in an algebraic expression are separated by '+' or '-' signs. Identifying these parts, we find the terms are:
There are exactly four terms in this expression.
Question 3
(a) and
(b) and
(c) and
(d) and
The correct option is (a) and .
In the expression , the terms are the parts separated by the addition or subtraction signs. Here, the terms are and . It is important to include the sign with the term.
Question 4
(a)
(b)
(c)
(d)
The correct option is (c) .
The term can be broken down into its constituent factors. The numerical factor is . The variable is squared (), meaning it appears twice as a factor (). Similarly, is squared (), appearing twice (). The variable appears once.
Therefore, the factors are , , , , , and , which can be written as .
Question 5
(a)
(b)
(c)
(d)
The correct option is (d) .
The coefficient of a variable in a term is the numerical factor that multiplies it. Sometimes, any factor in a term can be considered the coefficient of the remaining part of the term. In the term , if we consider as the variable of interest, the remaining part of the term is . This remaining part acts as the coefficient of .
Question 6
(a) ,
(b) ,
(c) ,
(d) ,
The correct option is (b) , .
Like terms are terms that have the same variables raised to the same powers. Let's examine each option:
- (a) and have different powers for and .
- (b) and both have variables , , and , each raised to the power of 1 (except which is power 2). They have the same variable parts ().
- (c) and have different powers for all variables.
- (d) and have different powers for and .
Therefore, and are the like terms.
Question 7
(a)
(b)
(c)
(d)
The correct option is (d) .
A binomial is an algebraic expression that contains exactly two unlike terms. Let's simplify each option:
- (a) has three unlike terms.
- (b) simplifies to , which is a monomial (one term).
- (c) has three unlike terms.
- (d) can be simplified by combining like terms: . This simplified expression has two unlike terms, making it a binomial.
Therefore, is the binomial expression.
Question 8
To find the sum of the two expressions, we add them together, combining like terms:
Group the like terms together:
Perform the addition/subtraction for each group of like terms:
Combining these results, the sum is:
The sum of the given expressions is .
Common mistakes
- Confusing coefficients with variables.
- Incorrectly identifying terms, especially with negative signs.
- Misclassifying expressions (e.g., calling a trinomial a binomial).
- Errors in determining factors or like terms due to variable powers.
Revision tips
- Review the definitions of monomial, binomial, and trinomial thoroughly.
- Practice identifying terms and coefficients in a variety of expressions.
- Pay close attention to the signs and powers of variables when finding factors and like terms.
- Work through each example and exercise step-by-step to reinforce understanding.
Practice MCQs
Q1. An algebraic expression with exactly three terms is called a:
Explanation: By definition, an algebraic expression containing three terms is known as a trinomial.
Q2. How many terms are present in the expression <math>3x^2y - 2y^2z - z^2x + 5</math>?
Explanation: The expression <math>3x^2y - 2y^2z - z^2x + 5</math> is composed of four distinct terms: <math>3x^2y</math>, <math>-2y^2z</math>, <math>-z^2x</math>, and <math>5</math>.
Q3. What are the terms of the expression <math>4x^2 - 3xy</math>?
Explanation: The terms of an expression are separated by '+' or '-' signs. Thus, the terms are <math>4x^2</math> and <math>-3xy</math>.
Q4. What are the factors of the term <math>-5x^2y^2z</math>?
Explanation: The factors of <math>-5x^2y^2z</math> are the numerical coefficient <math>-5</math> and the variables <math>x</math> (twice), <math>y</math> (twice), and <math>z</math> (once).
Q5. In the expression <math>-9xy^2z</math>, what is the coefficient of <math>x</math>?
Explanation: The coefficient of <math>x</math> in <math>-9xy^2z</math> is the remaining part of the term when <math>x</math> is excluded, which is <math>-9y^2z</math>.
Q6. Which of the following pairs are like terms?
Explanation: Like terms have the same variables raised to the same powers. <math>-10xyz^2</math> and <math>3xyz^2</math> are like terms because they both have the variables <math>x</math>, <math>y</math>, and <math>z</math> each raised to the power of 1.
Q7. Identify the binomial expression from the given options:
Explanation: A binomial is an expression with exactly two unlike terms. Option (d) simplifies to <math>2xy^2 + 5y</math>, which has two unlike terms.
Frequently asked questions
What is an algebraic expression?
An algebraic expression is a combination of constants and variables, connected by arithmetic operations like addition, subtraction, multiplication, and division.
What is the difference between a monomial, binomial, and trinomial?
A monomial has one term, a binomial has two terms, and a trinomial has three terms. These terms must be unlike terms.
How do I find the coefficient of a variable in an algebraic expression?
The coefficient is the numerical factor multiplying the variable(s) in a term. Sometimes, any factor can be considered the coefficient of the remaining part.
What are like terms?
Like terms are terms that have the same variables raised to the same powers. For example, <math>3x^2y</math> and <math>-5x^2y</math> are like terms.
How can these NCERT Solutions help with exam preparation?
These solutions provide clear, step-by-step explanations for each question, helping students understand the concepts of algebraic expressions and practice problem-solving techniques essential for exams.
What are factors in an algebraic expression?
Factors are the numbers and variables that are multiplied together to form a term. For instance, the factors of <math>4x^2y</math> are <math>4</math>, <math>x</math>, <math>x</math>, and <math>y</math>.
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