Page 305 - Start Up Mathematics_6

10. (a) Yes, x (b) No, inequality with variable x (d) 5y – 8 (e) –3y + 7 (f) 10 + 5y
(c) No, inequality with variable x 3. Multiples of 4, general expression = 4n
(d) No, its a numerical equation 4.
(e) No, inequality with variable p Number of 3 4 5 10 20 25 n
(f) Yes, p polygons
Number of
11. x 1 2 3 4 5 6 7 8 9 matchsticks 13 17 21 41 81 101 4n + 1
2x + 10 12 14 16 18 20 22 24 26 28
5. x 1 2 3 4 5 6 7 8 9
Clearly x = 5 is the solution as it makes the value of the
expression 2x + 10 equal to RHS (= 20) 2x – 9 –7 –5 –3 –1 1 3 5 7 9
12. m 1 2 3 4 5 6 7 8 9 Clearly, x = 7 is the solution of the equation.
3m – 7 –4 –1 2 5 8 11 14 17 20 6. 3 x 4 2 students, where x represents the number of rows.

Clearly x = 5 is the solution as it makes the value of 7. (a) q = 14 is the solution. (b) x = –4 is the solution.
3m – 7 equal to RHS (= 8)
Thinking Skills
13 . x 1 2 3 4 5 6 7 8 9 1. (a) 5(5) + 1, 5(10) + 1, 5n + 1 (b) 22 houses
x + 3 1 1 3 1 1 3 1 Number of
4 3 4 3 2 3 4 4 4 4 4 2 4 4 5 5 4 2. squares 3 4 5 10 n
Number of
Clearly x = 8 is the solution as it makes the value of 12 16 20 40 4n
x dots
4 + 3equal to RHS (= 5) Number of line
14. (5y + 20) km segments 14 19 24 49 5n – 1
15. y + 7 represents Sara’s age after 7 years
y – 3 represents Sara’s age 3 years ago 3. (a) 150 (n + 1) (b) ` 900
y + 4½ represents Sara’s age after 4½ years Values and Life Skills
y – 2½ represents Sara’s age 2½ years ago 1. Munny = P + 20; Bunny = P – 15

Review Exercises 2. (5v + 50) km 3. 3(7x + y)
Multiple Choice Questions Exemplar Problems
1. d 2. c 3. b 4. c 5. c 6. c 1. a 2. c 3. c 4. False
5. True 6. True 7. 10 t + 4
Solve Mentally 8. (i) x – 2 (ii) x + 35 (iii) x + 32 (iv) 8x
True or False
1. True 2. True 3. False 4. True 5. True Chapter 12
Fill in the Blanks Exercise 12.1
1. 2πr 2. algebraic expression 3. 3; 2; 0 1. 3 : 2 2. 3 : 4 3. 4 : 9 4. 3 : 8 5. 3
x 9 17
4. = 5. solution 6. – 50 6. (a) 1 : 6 (b) 1 : 10 (c) 3 : 5 (d) 1 : 4
4
Answer in One Word or a Line 7. (a) 4 : 3 (b) 3 : 4 (c) 4 : 7 (d) 3 : 7
1. Algebra is a branch of Mathematics in which we use 8. (a) 2 : 3 (b) 3 : 2 (c) 2 : 5 (d) 3 : 5
letters to denote variables and write rules or formulas 9. (a) 3 : 2 (b) 2 : 1 (c) 1 : 3 (d) 3 : 1
using them.
2. A constant always takes a fixed value, while a variable 10. (a) 9 : 2 (b) 17 : 3 (c) 23 : 9 (d) 15 : 1
can take different values. 11. Shilpa ` 276, Payal ` 184
3. An equation is a condition on a variable. An equality has 12. (a) 2 : 1 (b) 2 : 3 (c) 9 : 1 (d) 9 : 10
= sign while an inequality has < or > signs.
4. The constant value of the variable which satisfies the Exercise 12.2
equation is called the solution of the equation; one 1. (a), (b), (c)
5. 10x + 2y 6. x = 4 2. (a) x = 1 (b) x = 20 (c) x = 44 (d) x = 14
Let’s Evaluate 3. (a) 6 (b) 20 (c) 36 (d) 70
1. Variable is number of cows, Total number of legs = 4n 4. (a) Yes (b) No 5. 62 6. 49
n
2. (a) 6 + 5 (b) 2 (3x – 4y) (c) 3y + 13
3 5 7. 315 km 8. ` 6,000 9. 12

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