KSEEB Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.2

You can Download KSEEB Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.2 Questions and Answers to help you to revise the complete syllabus.

KSEEB Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.2

Question 1.
Find the product of the following pairs of monomials.
(i) 4, 7p
(ii) -4, 7p
(iii) -4p, 7pq
(iv) 4p³, -3p
(v) 4p, 0
Solution:
(i) 4, 7p = 28p
(ii) -4, 7p = -28p²
(iii) -4p, 7pq = -28p²q
(iv) 4p³, -3p = -12p²
(v) 4p, 0 = 0

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:
Since the area of rectangle is the product of length × Breadth
(i) p × q = pq
(ii) 10m × 5n = 50mn
(iii) 20x² × 5y² = 100x²y²
(iv) 4x × 3x² = 12x³
(v) 3mn × 4np = 12mn²p

Question 3.
Complete the table of products.

Solution:

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:
Volume of rectangular boxes is length × breadth × height
(i) 5a, 3a², 7a⁴
= 5 × 3 × 7 × a¹⁺²⁺⁴
= 105a⁷

(ii) 2p, 4q, 8r
= 2p, 4q, 8r
= 2 × 4 × 8pqr
= 64pqr

(iii) xy, 2x²y, 2xy²
= 1 × 2 × 2 × xy × x²y × xy²
= 4x⁴y⁴

(iv) a × 2b × 3c
= 1 × 2 × 3 × abc
= 6abc

Question 5.
Obtain the product of
(i) xy, yz, zx
(ii) a, -a², a³
(iii) 2, 4y, 8y², 16y³
(iv) a, 2b, 3c, 6abc
(v) m, -mn, mnp
Solution:
(i) xy × yz × zx
= x²y²z²

(ii) ax – a² × a³
= 1 × 1 × 1 × a × a² × a³
= 1 × a⁶
= -a⁶

(iii) 2 × 4y × 8y² × 16y³
= 2 × 4 × 8 × 16 × y × y² × y³
= 102y⁶

(iv) a × 2b × 3c × 6abc
= 1 × 2 × 3 × 6 × a × b × c × abc
= 36a²b²c²

(v) m × -mn × mnp
= 1 × -1 × 1 × m × -mn × mnp
= -1m²n²p