Selina Textbook Solutions: Algebraic Expressions | Mathematics Class 8 ICSE PDF Download

 Page 1


11. Algebraic Expressions 
EXERCISE 11(A) 
Question 1. 
Separate the constants and variables from the following : 
 
Solution: 
Clearly constants are : -7, v5, 8 – 5 
 
Question 2. 
Write the number of terms in each of the following polynomials. 
(i) 5x
2
 + 3 x ax 
(ii) ax ÷ 4 – 7 
(iii) ax – by + y x z 
(iv) 23 + a x b ÷ 2. 
Solution: 
 
Page 2


11. Algebraic Expressions 
EXERCISE 11(A) 
Question 1. 
Separate the constants and variables from the following : 
 
Solution: 
Clearly constants are : -7, v5, 8 – 5 
 
Question 2. 
Write the number of terms in each of the following polynomials. 
(i) 5x
2
 + 3 x ax 
(ii) ax ÷ 4 – 7 
(iii) ax – by + y x z 
(iv) 23 + a x b ÷ 2. 
Solution: 
 
Question 3. 
Separate monomials, binomials, trinomials and polynomials from the following algebraic 
expressions : 
 
Solution: 
 
Question 4. 
Write the degree of each polynomial given below : 
 
Solution: 
(i) degree = 2 (Polynomial is xy + 7z) 
(ii) degree = 3 (Polynomial is x
2
 – 6x
3
 + 8 y) 
(iii) degree = 8 (Polynomial is y – 6y
2
 + 5y
8
) 
(iv) degree = 3 (Polynomial is xyz – 3) 
(v) degree = 4 (Polynomial is xy + yz
2
 – xz
3
) 
(vi) degree = 12 (Polynomial is x
5
y
7
 – 8x
3
y
8
 + 10x
4
, y
4
z
4
) 
Question 5. 
Write the coefficient of : 
(i) ab in 7abx , 
(ii) 7a in 7abx ; 
(iii) 5x
2
 in 5x
2
 – 5x ; 
(iv) 8 in a
2
 – 8ax + a ; 
(v) 4xy in x
2
 – 4xy + y
2
. 
Solution: 
(i) The coefficient of ab in 7abx = 7x 
(ii) The coefficient of 7a in 7abx = bx 
(iii) The coefficient of 5x
2
 in 5x
2
 – 5x = 1 
(iv) The coefficient of 8 in a
2
 – 8ax + a = – ax 
(v) The coefficient of 4xy in x
2
 – 4xy + y
2
 = -1 
Page 3


11. Algebraic Expressions 
EXERCISE 11(A) 
Question 1. 
Separate the constants and variables from the following : 
 
Solution: 
Clearly constants are : -7, v5, 8 – 5 
 
Question 2. 
Write the number of terms in each of the following polynomials. 
(i) 5x
2
 + 3 x ax 
(ii) ax ÷ 4 – 7 
(iii) ax – by + y x z 
(iv) 23 + a x b ÷ 2. 
Solution: 
 
Question 3. 
Separate monomials, binomials, trinomials and polynomials from the following algebraic 
expressions : 
 
Solution: 
 
Question 4. 
Write the degree of each polynomial given below : 
 
Solution: 
(i) degree = 2 (Polynomial is xy + 7z) 
(ii) degree = 3 (Polynomial is x
2
 – 6x
3
 + 8 y) 
(iii) degree = 8 (Polynomial is y – 6y
2
 + 5y
8
) 
(iv) degree = 3 (Polynomial is xyz – 3) 
(v) degree = 4 (Polynomial is xy + yz
2
 – xz
3
) 
(vi) degree = 12 (Polynomial is x
5
y
7
 – 8x
3
y
8
 + 10x
4
, y
4
z
4
) 
Question 5. 
Write the coefficient of : 
(i) ab in 7abx , 
(ii) 7a in 7abx ; 
(iii) 5x
2
 in 5x
2
 – 5x ; 
(iv) 8 in a
2
 – 8ax + a ; 
(v) 4xy in x
2
 – 4xy + y
2
. 
Solution: 
(i) The coefficient of ab in 7abx = 7x 
(ii) The coefficient of 7a in 7abx = bx 
(iii) The coefficient of 5x
2
 in 5x
2
 – 5x = 1 
(iv) The coefficient of 8 in a
2
 – 8ax + a = – ax 
(v) The coefficient of 4xy in x
2
 – 4xy + y
2
 = -1 
Question 6. 
In  xy
2
z
3
, write the coefficient of 
 
Solution: 
 
Question 7. 
In each polynomial, given below, separate the like terms : 
 
Page 4


11. Algebraic Expressions 
EXERCISE 11(A) 
Question 1. 
Separate the constants and variables from the following : 
 
Solution: 
Clearly constants are : -7, v5, 8 – 5 
 
Question 2. 
Write the number of terms in each of the following polynomials. 
(i) 5x
2
 + 3 x ax 
(ii) ax ÷ 4 – 7 
(iii) ax – by + y x z 
(iv) 23 + a x b ÷ 2. 
Solution: 
 
Question 3. 
Separate monomials, binomials, trinomials and polynomials from the following algebraic 
expressions : 
 
Solution: 
 
Question 4. 
Write the degree of each polynomial given below : 
 
Solution: 
(i) degree = 2 (Polynomial is xy + 7z) 
(ii) degree = 3 (Polynomial is x
2
 – 6x
3
 + 8 y) 
(iii) degree = 8 (Polynomial is y – 6y
2
 + 5y
8
) 
(iv) degree = 3 (Polynomial is xyz – 3) 
(v) degree = 4 (Polynomial is xy + yz
2
 – xz
3
) 
(vi) degree = 12 (Polynomial is x
5
y
7
 – 8x
3
y
8
 + 10x
4
, y
4
z
4
) 
Question 5. 
Write the coefficient of : 
(i) ab in 7abx , 
(ii) 7a in 7abx ; 
(iii) 5x
2
 in 5x
2
 – 5x ; 
(iv) 8 in a
2
 – 8ax + a ; 
(v) 4xy in x
2
 – 4xy + y
2
. 
Solution: 
(i) The coefficient of ab in 7abx = 7x 
(ii) The coefficient of 7a in 7abx = bx 
(iii) The coefficient of 5x
2
 in 5x
2
 – 5x = 1 
(iv) The coefficient of 8 in a
2
 – 8ax + a = – ax 
(v) The coefficient of 4xy in x
2
 – 4xy + y
2
 = -1 
Question 6. 
In  xy
2
z
3
, write the coefficient of 
 
Solution: 
 
Question 7. 
In each polynomial, given below, separate the like terms : 
 
Solution: 
 
EXERCISE 11(B) 
Question 1. 
Evaluate : 
 
Solution: 
 
Page 5


11. Algebraic Expressions 
EXERCISE 11(A) 
Question 1. 
Separate the constants and variables from the following : 
 
Solution: 
Clearly constants are : -7, v5, 8 – 5 
 
Question 2. 
Write the number of terms in each of the following polynomials. 
(i) 5x
2
 + 3 x ax 
(ii) ax ÷ 4 – 7 
(iii) ax – by + y x z 
(iv) 23 + a x b ÷ 2. 
Solution: 
 
Question 3. 
Separate monomials, binomials, trinomials and polynomials from the following algebraic 
expressions : 
 
Solution: 
 
Question 4. 
Write the degree of each polynomial given below : 
 
Solution: 
(i) degree = 2 (Polynomial is xy + 7z) 
(ii) degree = 3 (Polynomial is x
2
 – 6x
3
 + 8 y) 
(iii) degree = 8 (Polynomial is y – 6y
2
 + 5y
8
) 
(iv) degree = 3 (Polynomial is xyz – 3) 
(v) degree = 4 (Polynomial is xy + yz
2
 – xz
3
) 
(vi) degree = 12 (Polynomial is x
5
y
7
 – 8x
3
y
8
 + 10x
4
, y
4
z
4
) 
Question 5. 
Write the coefficient of : 
(i) ab in 7abx , 
(ii) 7a in 7abx ; 
(iii) 5x
2
 in 5x
2
 – 5x ; 
(iv) 8 in a
2
 – 8ax + a ; 
(v) 4xy in x
2
 – 4xy + y
2
. 
Solution: 
(i) The coefficient of ab in 7abx = 7x 
(ii) The coefficient of 7a in 7abx = bx 
(iii) The coefficient of 5x
2
 in 5x
2
 – 5x = 1 
(iv) The coefficient of 8 in a
2
 – 8ax + a = – ax 
(v) The coefficient of 4xy in x
2
 – 4xy + y
2
 = -1 
Question 6. 
In  xy
2
z
3
, write the coefficient of 
 
Solution: 
 
Question 7. 
In each polynomial, given below, separate the like terms : 
 
Solution: 
 
EXERCISE 11(B) 
Question 1. 
Evaluate : 
 
Solution: 
 
 
Solution: 
Question 2. 
Add :