## ML Aggarwal Class 8 Solutions for ICSE Maths Chapter 10 Algebraic Expressions and Identities Ex 10.2

Question 1.

Find the product of:

(i) 4x^{3} and -3xy

(ii) 2xyz and 0

(iii) –\(\frac{2}{3}\)p^{2}q, \(\frac{3}{4}\)pq^{2} and 5pqr

(iv) -7ab,-3a^{3} and –\(\frac{2}{7}\)ab^{2}

(v) –\(\frac{1}{2}\)x^{2} – \(\frac{3}{5}\)xy, \(\frac{2}{3}\)yz and \(\frac{5}{7}\)xyz

Solution:

Question 2.

Multiply:

(i) (3x – 5y + 7z) by – 3xyz

(ii) (2p^{2} – 3pq + 5q^{2} + 5) by – 2pq

(iii) (\(\frac{2}{3}\)a^{2}b – \(\frac{4}{5}\)ab^{2} + \(\frac{2}{7}\)ab + 3) by 35ab

(iv) (4x^{2} – 10xy + 7y^{2} – 8x + 4y + 3) by 3xy

Solution:

Question 3.

Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively:

(i) (p^{2}q, pq^{2})

(ii) (5xy, 7xy^{2})

Solution:

Question 4.

Find the volume of rectangular boxes with the following length, breadth and height respectively:

(i) 5ab, 3a^{2}b, 7a^{4}b^{2}

(ii) 2pq, 4q^{2}, 8rp

Solution:

Question 5.

Simplify the following expressions and evaluate them as directed:

(i) x^{2}(3 – 2x + x^{2}) for x = 1; x = -1; x = \(\frac{2}{3}\) and x = –\(\frac{1}{2}\)

(ii) 5xy(3x + 4y – 7) – 3y(xy – x^{2} + 9) – 8 for x = 2, y = -1

Solution:

Question 6.

Add the following:

(i) 4p(2 – p^{2}) and 8p^{3} – 3p

(ii) 7xy(8x + 2y – 3) and 4xy^{2}(3y – 7x + 8)

Solution:

Question 7.

Subtract:

(i) 6x(x – y + z)- 3y(x + y – z) from 2z(-x + y + z)

(ii) 7xy(x^{2} -2xy + 3y^{2}) – 8x(x^{2}y – 4xy + 7xy^{2}) from 3y(4x^{2}y – 5xy + 8xy^{2})

Solution: