Page 382 - Start Up Mathematics_8 (Non CCE)

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Exercise 5.7 6. (a) –3lm (b) –3x + 36xy – 14y 2
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1. (a) x + 8x + 12 (b) x – x – 12 (c) x – 12x + 35 (c) –25l + 94lm – 17m 2
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(d) 16x + 16x – 21 (e) 9 y 2 + 3 y - 8 (f) x 2 + 29 x + 1 8. (a) 9,801 (b) 11,236 (c) 2,491 (d) 14,400 (e) 1,224
16 2 10 9. (a) 256y – 1 (b) x – 256 10. +5
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(g) 49x – 63x y + 18x y (h) l 4 + l 2 - 3
4 8 Thinking Skills
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2. (a) 10,815 (b) 11,448 (c) 9,312 (d) 9,690 1. (a) 4x + 25y + 49z – 20xy – 70yz + 28zx
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(e) 2,832 (f) 924 (g) 9,98,980 (h) 2,115 (b) 25a 2 + b 2 + 9 c 2 - 5ab + bc - 15 ca
Review Exercises 4 16 4 2
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Multiple Choice Questions (c) 4x + y + 64z – 4xy – 16yz + 32zx
1. c 2. b 3. c 4. a 5. b 2. (a) –4bc + 4ca (b) 0
6. d 7. a Exemplar Problems
Solve Mentally 1. a 2. 8x 3. True
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True or False 2 2 2 2 2 2 3 2
1. True 2. False 3. True 4. False 4. 2ab c – 14a b c + 7a bc 5. –b + 2b + 7b – 8; 16
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Fill in the Blanks 6. 51 7. 7xy (x + y )
1. terms 2. three 3. like, unlike 4. binomials
5. monomials, associativity Chapter 6
Answer in One Word or a Line Exercise 6.1
1. An algebraic expression is a phrase with one or more 1. (a) 4 (b) 5 (c) 0 (d) 9 (e) 0
algebraic terms. It is a combination of constants and 2. (a) and (c)
variables connected by + or – signs. 3. Standard form Degree
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For example, 3x + 7y + 2xy + 5 3 2
2. Each term in an algebraic expression is a product of one (a) 3x + x – 7x + 4 3
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or more number(s) and/or literal(s) which are the factors (b) x + 3x – 4 4
of that term. 61
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3. An algebraic identity is a statement of equality between (c) x + x + 1 2
two algebraic expressions that is satisfied by all the values 30
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of the variables. (d) x – 15x + 56 6
4. An algebraic identity has ‘≡’ sign whereas an equation Exercise 6.2
has ‘=’ sign.
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5. Distributive property of multiplication of literals over 1. (a) 2x y z (b) 5x y z (c) –21a b
their addition. (d) –19a bc (e) 8p q r (f) –6p q r
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6. (a) (p + q) = p + 2pq + q (b) (p – q) = p – 2pq + q 2
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(c) (p + q)(p – q) = p – q 2 2. (a) 40x y z u (b) –6x y z (c) 25a b cd 2
(d) 41a b c
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Let’s Evaluate
23 2 Exercise 6.3
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1. (a) ab 2 + a b (b) 7x + 3 2
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20 15 (a) x – 3x (b) y – 8y + 5y (c) x – y + 3z
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47 79 11 101 3
2. (a) x 3 - x 2 - x - 3
42 42 42 42 (d) x - x 2 + 1 x (e) - 1 p 4 + 2 p 2 + 22 +p 2
31 29 3 3 6 2
(b) xy - xz - yz
14 12 2 (f) 1 x 3 + 3 x 2 +-x 3
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12 32 22
3. –x – x + 12 4. (a) 300x y z (b) 3.45x y z 2 2
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4 2 (g) –2x – 5x y + 6x y (h) –9xy z + 7x yz
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5. (a) - abc + ab c (b) 8x + 20x y – 6xy – 15y 3
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(c) 32x – 28x + 49x + 24 Quiz
27 9 9 3 –24abc
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(d) x y z - x y z + x yz - x yz 2
10 20 5 10 Exercise 6.4
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(e) 16x – 16x – 45 (f) 16 x 2 - 4 y 2 1. (a) x – x + 1 (b) –2y + 7 (c) 2x + 1
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