NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.2 are part of NCERT Solutions for Class 8 Maths. Here we have given NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.2.
- Algebraic Expressions and Identities Class 8 Ex 9.1
- Algebraic Expressions and Identities Class 8 Ex 9.3
- Algebraic Expressions and Identities Class 8 Ex 9.4
- Algebraic Expressions and Identities Class 8 Ex 9.5
| Board | CBSE |
| Textbook | NCERT |
| Class | Class 8 |
| Subject | Maths |
| Chapter | Chapter 9 |
| Chapter Name | Algebraic Expressions and Identities |
| Exercise | Ex 9.2 |
| Number of Questions Solved | 5 |
| Category | NCERT Solutions |
NCERT Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.2
Ex 9.2 Class 8 Maths Question 1.
Find the product of the following pairs of monomials :
(i) 4, 7p
(ii) -4p, 7p
(iii) – 4p, 7pq
(iv) 4p3 , – 3p
(v) 4p, 0
Solution:
(i) 4 x 7p = (4 x 7) x p = 28p
(ii) – 4 p x 7p = (- 4 x 7) x (px P)
= -28p1 + 1 = – 28p2
(iii) -4px 7pq = (- 4 x 7) x (p x p x q)
= -28 p1+1q = – 28p2q
(iv) 4p3 x – 3p = (4 x – 3) x (p3 x p)
= – 12p3+1 = =-12p4
(v) 4p x 0 = (4 x 0) x p = 0 x p = 0
Ex 9.2 Class 8 Maths Question 2.
Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively :
(p, q); (10m, 5n); (20x2, 5y2); (4x, 3x2); (3mn, 4np)
Solution:
We know that the area of a rectangle = l x b, where l = length and b = breadth.
Therefore, the areas of rectangles with pair of monomials (p, q); (10m, 5n); (20x2, 5y2); (4x, 3x2) and (3mn, 4np) as their lengths and breadths are given by
pxq=pq
10 m x 5n = (10 x 5) x (m x n) = 50 mn
20x2 x 5y2 = (20 x 5) x (x2 x y2) = 100x2y2
4x x 3x2 = (4 x 3) x (x x x2)
= 12x2
and, 3 mn x 4np = (3×4 )x(mxnxnxp)
=12 mn2p
Ex 9.2 Class 8 Maths Question 3.
Complete the table of products :
Solution:
Completed table is as under :
Ex 9.2 Class 8 Maths Question 4.
Obtain the volume of rectangular boxes with the following length, breadth and height respectively
(i) 5a, 3a2, 7a4
(ii) 2p, 4q, 8r
(iii) xy, 2x2y, 2xy2
(iv) a, 2b, 3c
Solution:
(i) Required volume = 5a x 3a2 x 7a4
= (5 x 3 x 7) x (a x a2 x a4)
= 105a1+2+4 =105a7
(ii) Required volume = 2p x 4q x 8r
= (2 x 4 x 8 )x p x q x r = 64 pqr
(iii) Required volume =xy x 2x2y x 2xy2
= (1 x 2 x 2) x (x x x2 x x x y x y x y2)
= 4x1+2+1 y1+1+2 = 4x4y4
(iv) Required volume =a x 2b x 3c
= (1 x 2 x 3) x (a x b x c)
= 6abc
Ex 9.2 Class 8 Maths Question 5.
Obtain the product of
(i) xy, yz, zx
(ii) a, – a2, a3
(iii) 2, 4y, 8y2, 16y3
(iv) a, 26, 3c, 6a6c
(v) m, – mn, mnp
Solution:
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