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Page No 68:

Question O1:

Which is the numerical co-efficient in 4x2y?

Answer:

The numerical co-efficient in is 4.

Page No 68:

Question W1:

Classify the following into constants and variables.

Answer:

Constants: 5, π, 8, − 7,

Variables:

Page No 68:

Question O2:

Mention the absolute term in 3x2 − 6x −8.

Answer:

The absolute term in is −8.

[The constant term in an expression is called an absolute term.]

Page No 68:

Question O3:

Given an example for binomial expression.

Answer:

5x2 − 3x

Here, number of terms is two.

5x2 − 3x is a binomial expression.



Page No 69:

Question W2:

Write the numerical co-efficient of the following terms.

(1) −3x2

(2)

(3) 4y

(4) 0.3m

(5) −1.5p

(6) pqr

Answer:

(1) Numeral coefficient = − 3

(2) Numeral coefficient =

(3) Numeral coefficient = 4

(4) Numeral coefficient = 0.3

(5) Numeral coefficient = −1.5

(6) Numeral coefficient = 1

Page No 69:

Question W3:

Write the co-efficient as indicated below:

1. In 27 abc

(a) The numerical co-efficient of abc ________.

(b) Algebraic co-efficient of 27 ab ________.

(c) Algebraic co-efficient of 27 ac _______.

(d) Algebraic co-efficient of 27 bc _______.

(e) Algebraic co-efficient of 27 _______.

2. In

(a) Numerical co-efficient of xy2z _______.

(b) Algebraic co-efficient of_______.

(c) Algebraic co-efficient of_______.

(d) Algebraic co-efficient of_______.

(e) Algebraic co-efficient of_______.

Answer:

(1)

(a) The numerical co-efficient of abc 27 .

(b) Algebraic co-efficient of 27 ab c .

(c) Algebraic co-efficient of 27 ac b .

(d) Algebraic co-efficient of 27 bc a .

(e) Algebraic co-efficient of 27 abc .

(2)

(a) Numerical co-efficient of xy2z.

(b) Algebraic co-efficient of z .

(c) Algebraic co-efficient of y2 .

(d) Algebraic co-efficient of x .

(e) Algebraic co-efficient of xy2z .

Page No 69:

Question W4:

Using the terms given below form the sets of like terms:

Answer:

Sets of like terms are given below:

(1)

(2)

(3)

(4)

Page No 69:

Question W5:

Write the least three sets containing 5 terms in each, by using the unlike terms given below:

Answer:

Sets containing 5 terms:

(1)

(2)

(3)



Page No 70:

Question W6:

Classify the following into monomial, binomial and trinomials.

(1) a2 + a − 2

(2) x2 + 2y2

(3) 3x2 + 4y + 5z

(4) ax2 + bx + c

(5) x − 5

(6) 8mn3

(7) a2b

(8)

(9) 7k + l

(10) 12ab

Answer:

(1) Trinomial

(2) Binomial

(3) Trinomial

(4) Trinomial

(5) Binomial

(6) Monomial

(7) Binomial

(8) Monomial

(9) Binomial

(10) Monomial

Page No 70:

Question W7:

Pickout and write the absolute term from the expression given below:

(1) x2 + 5x = 8

(2) 5x3 − 4x2 + 3x + 18

(3) 6x2y + 8y2 + xy − 10

(4)

Answer:

(1) Absolute Term = 8

(2) Absolute Term = 18

(3) Absolute Term = − 10

(4) Absolute Term =



Page No 71:

Question W1:

Add:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

Page No 71:

Question O1:

What is the sum of 9x and 3x?

Answer:

The sum of 9x and 3x is .

Page No 71:

Question O2:

What do you get when −2m is added to −4m?

Answer:

On adding −2m and ­−4m, we get.



Page No 72:

Question W2:

Find the perimeter of the figures given below.

(1)

(2)

(3)

(4)

Answer:

(1) Perimeter

(2) Perimeter

(3) Perimeter

(4) Perimeter



Page No 73:

Question W1:

Find the sum of:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

Page No 73:

Question O1:

What is the sum of +4xy and −7xy?

Answer:

3xy

Page No 73:

Question O2:

What is the sum of −6a, + 2a and −5a?

Answer:

9a



Page No 74:

Question O1:

What do you get when 3q is added to 4p?

Answer:

On adding 3q to 4q, we get .

Page No 74:

Question W1:

Find the sum of the following.

(1) 3b and −2a

(2) −7x and 3y

(3) 5a and 2b

(4) 7m and −5n

(5) 15xy and 5pq

(6) 4x2 and b2

(7) 5mn2 and 9m2n

(8) 6a2bc and 4x2yz

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

Page No 74:

Question O2:

What is the sum of 5p, 6q and 7r?

Answer:

On adding 5p, 6q and 7r, we get .

Page No 74:

Question W2:

Simplify:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

 



Page No 75:

Question W3.1:

If the number of students in four classes of a school are 8x, 10x, 15x and 25x respectively, how many students are there altogether in the school?

Answer:

Total number of students

Page No 75:

Question W3.2:

If the number of benches and chairs in a school are 4b and 5c respectively, what is the total number of chairs and benches?

Answer:

Total number of chairs and benches

Page No 75:

Question W3.3:

If there are ‘12b’ bananas, ‘9a’ apples and ‘5p’ papayas in the basket of Kenchappa the fruit seller, find the total number of fruits.

Answer:

Total number of fruits

Page No 75:

Question W3.4:

Thimmakka has planted ‘8g’ sapling in a year. She planted ‘10g’ sapling next year. How many sapling did she plant altogether?

Answer:

Total number of saplings planted



Page No 77:

Question O1:

What do you get when 10p is subtracted from 6p?

Answer:

4p

Page No 77:

Question W1:

Subtract:

(1) 5a from 3a

(2) −3b from 2b

(3) 3x2 from (−8x2)

(4) −11xyz from −7xyz

(5) 7xy from 14xy

(6) What should be added to 8ab to get 15ab?

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

Thus, should be added to to get.

Page No 77:

Question O2:

What do you get when 5n is subtracted from 3m?

Answer:

Page No 77:

Question W2:

Subtract:

(1) 5y from 4x

(2) −2a from 3b

(3) 5p from −12p

(4) −4c from −7d

(5) 5pq from 7mn

Answer:

(1)

(2)

(3)

(4)

(5)

Page No 77:

Question W3:

(1) Subtract the sum of 3a and 4a from 9a

(2) Subtract (−5xy + 9yz) from (3xy − 4yz)

(3) Subtract (7m2 − 2m) from (−4m − 7m2)

(4) Subtract (6a − 4b + c) from (−a + 3b − 5c)

(5) Subtract (−4x − 8y + 7) from (3y − 7x + 1)

(6) How much should be added to (5x − 3y) to get (3x − 5y)?

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

Thus, should be added to to get.



Page No 78:

Question W4:

(1) Krishna buys ‘8a’ bananas and sells ‘3a’ bananas out of them. How many bananas are left with him?

(2) Joseph has Rs 30x with him. In that if he spend Rs 7x for books and Rs 5x for sweets, how much money is left with him?

Answer:

(1)

Therefore, bananas are left with Krishna.

(2)

Rs. is left with Joseph.



Page No 79:

Question W1:

Fill in the blanks with appropriate answers in the following:

(1)

(2)

(3)

(4)

(5)

(6)

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

Page No 79:

Question O1:

Give an example for commutative property of addition.

Answer:

An example in which commutative property of addition is used is .

Page No 79:

Question W2:

Mention the value of the variable in each of the following:

(1)

(2)

(3)

(4)

(5)

Answer:

(1)

(2)

(3)

(4)

(5)

Page No 79:

Question O2:

Identify he property used in

(m + n) + p = m + (n + p)

Answer:

The property used in is the associative law of addition.



Page No 81:

Question W1:

Multiply:

(1) 3x by 4y

(2) 2y by 4y

(3) 8a by 4m

(4) −4x by 8x

(5) −5a by −8b

(6) −6p by 4pq

(7) 2a2 by 5a2

(8) 3x2b2 by 5x

(9) −7m2n2 by 4m

(10) −5a2b by −7ab2

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

Page No 81:

Question O1:

What is the product of 2x and 5x?

Answer:

The product of 2x and 5x is.

Page No 81:

Question O2:

How many marbles are there in 5n boxes, each containing 3m marbles?

Answer:

15mn

Explanation: To find the required number of marbles in the boxes, we need to multiply the number of the boxes to the number of the marbles in each. Thus, the number of the boxes is

.

Page No 81:

Question W2.1:

If the side of a square is 8a cm, what is its area?

Answer:

Side of a square

Area of square

Page No 81:

Question W2.2:

The length of a rectangle is 3x cm and its breadth is 5y cm. What is the area of the rectangle?

Answer:

Area of rectangle



Page No 84:

Question O1:

Give an example for commutative property of multiplication.

Answer:

An example of commutative property of multiplication is .

Page No 84:

Question W1:

Fill in the blanks is the following and also mention the law which is used.

(1)

(2)

(3)

(4)

(5)

(6)

Answer:

(1)

Here, commutative law of multiplication is used.

(2)

Here, associative law of multiplication is used.

(3)

Here, commutative law of multiplication is used.

(4)

Here, distributive law of multiplication is used.

(5)

Here, distributive law of multiplication is used.

(6)

Here, associative law of multiplication is used.

Page No 84:

Question O2:

Identify the property used in.

Answer:

The property used in is the associative law of multiplication.

Page No 84:

Question O3:

Identify the property used in the equation.

Answer:

The property used in is the distributive law of multiplication.



Page No 85:

Question W2:

If a = 1, b = 2 and c = −3, put the values in the given equations and mention the law which they prove.

(1) [2a + (−3b)] c = 2ac − 3bc

(2) a × (2b × 3c) = (a × 2b) × 3c

Answer:

(1)

The equation proves the distributive law.

(2)

LHS = RHS

The equation proves the associative law.

Page No 85:

Question O1:

What is the product of 2b and (3a − 4c)?

Answer:

Page No 85:

Question O2:

What is the product of (6x + 7y) and 3x?

Answer:



Page No 86:

Question W1:

Multiply:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

(11)

(12)



Page No 87:

Question 1:

Find the product of the following:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)

Answer:

(1)

(2)

(3)

(4)

(5)

(6)

(7)

(8)

(9)

(10)



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