Chapter 8 Algebraic Expressions and Operations on Them Set 8.2
Question 1.
Add:
i. 9p + 16q; 13p + 2q
ii. 2a + 6b + 8c; 16a + 13c + 18b
iii. 13x² – 12y²; 6x² – 8y²
iv. 17a²b² + 16c; 28c – 28a²b²
v. 3y² – 10y + 16; 2y – 7
vi. – 3y² + 10y – 16; 7y² + 8
Solution:
i. (9p + 16q) + (13p + 2q)
= (9p + 13p) + (16q + 2q)
= 22p + 18q
ii. (2a + 6b + 8c) + (16a + 13c + 18b)
= (2a + 16a) + (6b + 18b) + (8c + 13c)
= 18a + 24b + 21c
iii. (13x² – 12y²) + (6x² – 8y²)
= (13x² + 6x²) + [(-12y²) + (-8y²)]
= 19x² + (-20y²)
= 19x² – 20y²
iv. (17a²b² + 16c) + (28c – 28a²b²)
= [17a²b² + (-28a²b²)] + (16c + 28c)
= -11a²b² + 44c
v. (3y² – 10y + 16) + (2y – 7)
= 3y² + (-10y + 2y) + (16 – 7)
= 3y² – 8y + 9
vi. (-3y² + 10y – 16) + (7y² + 8)
= (-3y² + 7y²) + (10y) + (-16 + 8)
= 4y² + 10y – 8
Intext Questions and Activities
Question 1.
Answer the following questions. (Textbook pg. no. 57)
- 3x + 4y = How many?
- 3 guavas + 4 mangoes = 7 guavas.
- 7m – 2n = 5m.
Solution:
- 3x and 4y are unlike terms. Hence, they cannot be added, further to get a single term.
- No. Guava and mango are different fruits. Hence, 3 guavas + 4 mangoes & 7 guavas.
- No. 7m and 2n are unlike terms. Hence, 7m – 2n ≠ 5m.