Page 395 - Start Up Mathematics_8 (Non CCE)

1 1 1 5 2 3. (a) 12x – 15x + 3; (i) 66 (ii) –3
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6. (a) (b) (c) (d) 0 (e) (e) 2
2 6 3 6 3 (b) a + a + a + 5; (i) 5 (ii) 8 (iii) 4
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1 3 1 2 2 3 3
7. (a) (b) (c) (d) 0 4. (i) 4ac (ii) 3x + 4xy – y (iii) x + y
2 10 10 (iv) 2.25x – 16y 2
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5. (i) a – 2a b + b (ii) 40x (iii) 98m + 128n
Some NCERT Textbook Questions (iv) 41m + 80m + 41n (v) 4p – 4q
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Chapter 1 (vi) a b + b c (vii) m + n m 2
1. Associativity 6. Students to do on their own.
2. No, because the product is not 1. 7. (i) 10404 (ii) 996004 (iii) 6396 (iv) 9.975
–1 8. (i) 10712 (ii) 26.52 (iii) 10094 (iv) 95.06
3.
–11 –10 –9 –8 –7 –6 –5 –4 –3 –2 –1 0 Chapter 6
11 11 11 11 11 11 11 11 11 11 11 1. (i) x 3 (ii) x y (iii) –2a b
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2 4
–7 –6 –5 –4 –3 –2 –1 1 2 2 3
4. , , , , , , , 0, …, , 1
20 20 20 20 20 20 20 20 20 2. (i) 5(3x + 5) (ii) 2y(x + 5) (iii) r(p + q)
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(There can be many more such rational numbers) (iv) 4(y + 5y + 3) (v) (x + 2)(x + 3)
97 98 99 100 101 102 103 104 105 106
5. , , , , , , , , , Chapter 7
160 160 160 160 160 160 160 160 160 160
(There can be many more such rational numbers) 1. (i) (x + 8)(x + y) (ii) (3x + 1)(5y – 2)
(iii) (5p + 3)(3q + 5) (iv) (z –7)(1 – xy)
Chapter 2 2. (i) (a + 4) (ii) (l – m) (iii) (3xy – 4)(3xy + 4)
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1 1 1 1 (iv) (3x – 2)(2y – 3) (v) (a – b)(a + b)(a + b )
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1. (i) (ii) (iii) (5 ) (iv) (v)
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(–4) 3 2 6 (3) 2 (–14) 3 (vi) z(2x – z)(2x – 2xz + z ) (vii) (a – b) (a + b)
1 625t 4 (viii) (p + 8)(p – 2)
2. (i) 5 (ii) (iii) 29 3. (i) (ii) 5 5
2 2 Chapter 8
–7
–6
4. (i) 1 × 10 (ii) 1.6 × 10 –19 (iii) 5 × 10 8
–5
(iv) 1.275 × 10 (v) 7 × 10 –2 1. (a) x = 9 (b) x = 2 (c) y = 2.4 (d) x = – 5
Chapter 3 2. 1 3. 19 4. (a) t = – 1 (b) x = 40 (c) y = 7 3
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1. These numbers ends with 5. 26 (or 62) 6. Length = 275 m; breadth = 100 m
(i) 7 (ii) 3 (iii) 8 (iv) 2 (v) 0 (vi) 2 4
(vii) 0 (viii) 0 7. 72 8. (a) y = –8 (b) y = – 5
2. (i) 1 + 3 + 5 + 7 + 9 + 11 + 13 9. Hari’s age = 20 years; Harry’s age = 28 years
(ii) 1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21 Chapter 9
3. (i) 6, 8, 10 (ii) 14, 48, 50 (iii) 16, 63, 65 –4
(iv) 18, 80, 82 1. 10 cm; 2 cm
4. (i) 7; 42 (ii) 5; 30 (iii) 7; 84 (iv) 3; 78 2. 21 m 7 6
(v) 2; 54 (vi) 3; 48 3. (i) 2.25 × 10 crystals (ii) 5.4 × 10 crystals
5. 49 6. (i) 48 (ii) 67 (iii) 59 (iv) 37 4. 4 → 25,000; 5 → 20,000; 8 → 12,500; 10 → 10,000;
7. (i) 1.6 (ii) 2.7 (iii) 7.2 (iv) 6.5 (v) 5.6 20 → 5,000
Amount given to a winner is inversely proportional to the
Chapter 4 number of winners.
1. (i) 3 (ii) 2 (iii) 3 (iv) 5 (v) 10 5. 4 6. (i) 6 days (ii) 6 persons
2. (i) 3 (ii) 2 (iii) 5 (iv) 3 (v) 11
3. (i) False (ii) True (iii) False (iv) False Chapter 11
(v) False (vi) False (vii) True 1. 25 matches
4. 11, 17, 23, 32 2. ` 2400
3. 10%, cricket → 30 lakh; football → 15 lakh;
Chapter 5 other games → 5 lakh
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1. (i) 0 (ii) ab + bc + ac (iii) –p q + 4pq + 9 4. ` 1,40,000
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(iv) 2(l + m + n + lm + mn + nl) Chapter 12
2. (a) 8a – 2ab + 2b – 15 1. ` 34.80 2. Gain of 2% 3. ` 2,835 4. ` 18,342.50
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(b) p q – 7pq + 8pq – 18 q + 5p + 28 5. ` 2,000
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