Page 380 - Start Up Mathematics_8 (Non CCE)

Exercise 4.2 3. The method is applicable for numbers upto 6 digits which
1. (a) –1,728 (b) –12,167 (c) –42,875 (d) –74,088 are perfect cubes.
2. (a), (b), (d) 4. 3
3. (a) –19 (b) –46 (c) –28 (d) –121 (e) –95 5. 3 is called the radical, 3 is called the index of the radi-
cal and the number whose cube root is to be calculated
2,197 21
4. (a) 250.047 (b) –0.009261 (c) or 34 is called the radicand. For example, 64 = 4 = 64 = 4
3
3
64 64
- 29791 199
(d) or 137- (e) 0.000512 index radicand
216 216 Let’s Evaluate
(f) –345.948408 1. (a) 6,859 (b) 17,576 (c) 1,17,649 (d) 18,60,867
12 - 8 41 - 29 - 1 2. (a) 59,319 (b) 97,336 (c) 7,53,571 (d) 6,58,503
5. (a) (b) (c) (d) (e)
17 13 50 100 5 3. (a) 7 (b) 6 (c) 10 4. 2
Exercise 4.3 5. 2 6. (a) –136 (b) 144 (c) 154
1. (a) 6 (b) 4 (c) 18 Thinking Skills
(d) 2 (e) 9 1. d 2. c 3. a
2. (a) 5 (b) 2 (c) 2 Exemplar Problems
(d) 45 (e) 5
3. (a) 9 (b) 16 (c) 18 (d) 25 1. a 2. 2 3. False 4. False
(e) 30 (f) 34 (g) 42 (h) 49 5. 6 6. 3.6
(i) 122 Chapter 5
4. 130 m 5. 135 cm
6. (a) 68 (b) 95 (c) 86 Exercise 5.1
(d) 59 (e) –70 1. Terms Coefficients Terms Coefficients
Exercise 4.4 (a) 12 1 (b) 4x y 4
2
1. (a) –7 (b) –160 (c) –19 (d) –72 x 1 –7x 3 –7
(e) 1.3 (f) –0.9 (g) 0.34 (h) –0.18 y 2 1 3y 4 3
3. (a) 22 (b) –45 (c) 28 (d) 48 –zx –1
3
(e) 120p 2 (f) 11.1 (g) 1 (h) or 0.75 1 1
4 (c) 2 a 2 (d) 9.2x 9.2
9 - 15 29 21 - 28
2
4. (a) (b) (c) (d) (e) –3a b –3 –4.1yz –4.1
13 17 27 - 10 19
2
13 2x yz 2 2
5. 7 6. 2 7. 3.3 m 8. cm or 1.44 cm
9
2. Monomials → (c), (d), (h) Binomials → (a), (f)
9. 0.06, 0.08 and 0.1 10. 14, 21 and 35 11. 16 and 24 Trinomials → (b), (e), (g)
Review Exercises 3. (a) 4xy, 2xy (b) x y , 10x y (c) xy z , 5xy z
2 3
2 4
2 4
2 3
Multiple Choice Questions Exercise 5.2
1. c 2. b 3. c 4. c 2 2 2 2
5. a 6. c 1. (a) 5a – 2ab – 2b (b) 5p q (c) –7px + qy + 12rz
Solve Mentally (d) 61 xy - 37 y - 23 x (e) 7p – 17pq + 5q + 8
2
2
True or False 14 10 35
1. True 2. False 3. True 4. True 5. False 19 2 25 3 28
6. True 7. False (f) 6 x + 2x + 6 x + 15
Fill in the Blanks 2. (a) –x + x – 12x – 5x + 10
3
2
4
1. 2,744 2. 2 3. 64 4. 7 5. 3 6. 13 2 10 251 10 xy
(b) - x 3 + x 2 + 2 +x 2 (c) yz - xz -
Answer in One Word or a Line 3 7 21 7 5
1. The cube of a number is the number with exponent 3 or (d) - 7 y 3 - 4 y 2 - 5 y + 1
raised to the power 3. 4 5 6
2. A number with exponent 3 or raised to the power 3 is 2 2 2
called cube. Whereas a number which is a product of three 3. –x – 9y + z – 13 4. 6p – 7q – 3r 5. 5a – 9b + 2c
identical numbers is called a perfect cube. For example, 6. –10x – 2y – 4z
3
4 is cube of 4 while, 2 × 2 × 2 = 8 is a perfect cube.
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