Page 341 - Start Up Mathematics_7

Fill in the Blanks Exercise 7.2

1. 3x – 2 2. unlike 3. subtracted 4. 5 1. (a) p = 9 (b) x = 0 (c) p = 17 (d) m = –2
1 2. (a) Subtract 4 from both sides ⇒ y = 2
5. 1 6. x – y 7. 5, 0 8. pq
3
3
2 (b) Subtract 5 from both sides ⇒ x = 3
Answer in One Word or a line
1. Degree of polynomial 3xy z + 7xyz – 2x is 4. (c) Add 6 on both sides ⇒ x = 19
2
2
2. x y and xy are unlike terms. (d) Multiply both sides by 2 ⇒ x = 16
2
2
3. Every constant is a polynomial of degree 0. 3. (a) Divide both sides by 2 ⇒ x – 1 = 5
4. Negative of a polynomial, i.e., a polynomial obtained by Add 1 on both sides ⇒ x = 6
changing signs of all the terms (b) Add 25 on both sides ⇒ 5x = 25
5. Coefficient of x is 5y and coefficient of xy is 5.
Dividing both sides by 5 ⇒ x = 5
Let’s Evaluate 1 x 1
1. (a) binomial (b) monomial (c) Subtract 2 from both sides ⇒ 2 = 2
(c) binomial (d) trinomial Multiply both sides by 2 ⇒ x = 1
2. (a) 4x (b) 3x (c) –5x z (d) –3x (d) Add 2 on both sides ⇒ –x = 8
2
2
3. 3a – 4ab + 3b 4. –x + 5x + 5 Multiply both sides by –1 ⇒ x = –8
2
2
2
5. 2y – 2xy 6. a – 15b – 26 5
2
7. –10 8. 3a + ab + 2; 35 9. a = 3 4. (a) y = 16 (b) x = 30 (c) x = 63 (d) x = 8
2
10. Number of segments if digit repeats Exercise 7.3
Digit
10 times 25 times 100 times 1. (a) s = –4 (b) q = 4 (c) m = 2 (d) x = –2
9 51 126 501 (e) s = –7 (f) m = 2 (g) x = 3 (h) x = 7
35
Thinking Skills (i) x = 11 (j) x = 11 (k) x = 5
1. x – 12 = 2(x – 17), where x is Karishma’s age 2. (a) 2m = 1, 2m + 3 = 4, 4m – 2 = 0
2. (a) 4x + 2(x + 2) where smallest integer is x n
(b) n + 3 = 0, 2n + 6 = 0, + 1 = 0
(b) 2[(2x – 8) + (x + 2)] where width of rectangle is x 3
(c) q + 5 = 0, 2q + 10 = 0, 3q + 15 = 0
Exemplar Problems
(d) 5x + 1 = 0, 10x + 2 = 0, 15x = –3
1. d 2. a 3. n, 6n 4. False
(Note: Answers of Q. 2 may vary)
5. –2p – 9pq + 6q 6. 4p qr 7. 10x – 8y + x
2
2
2
2
2
Exercise 7.4
8. 8x + 50 9. 18r + 6b = 6(3r + b)
1. 9 2. 30 3. 22, 23, 24 4. 30, 35
Chapter 7 5. 11 6. 39 7. 20 8. 34 9. 21
Exercise 7.1 10. 33, 52 11. 11, 7
2
1. (i) No (ii) Yes (iii) No (iv) Yes 12. 18 cm, 12 cm; 216 cm 13. 200 each
2. (a) Yes (b) Yes (c) No Review Exercises
b Multiple Choice Questions
3. (a) 9a + 6 = 24 (b) = 5 (c) 5y – 12 = 40
7 1. c 2. d 3. c 4. a
(d) 3y + 5 = 41, where Simran’s age is y Solve Mentally
(e) x + 2x + 2x = 180°, where vertex angle is x True or False
(f) n + (n + 2) = 44, where n is an odd number 1. True 2. False 3. False 4. True 5. False
4. (a) 7 added to x gives 9 6. True 7. False
(b) Three times p divided by sum of p and 5 gives 16 Fill in the Blanks

(c) A number exceeding 4 times p by 2 equals 20 1. 12 2. solution or root 3. 6
(d) Twice of x diminished by 5 gives 20 4. infinite 5. negative 6. 9

333