HBSE 7th Class Maths Solutions Chapter 12 Algebraic Expressions InText Questions

Haryana State Board HBSE 7th Class Maths Solutions Chapter 12 Algebraic Expressions InText Questions and Answers.

Haryana Board 7th Class Maths Solutions Chapter 12 Algebraic Expressions InText Questions

Try These (Page 230)

Question 1.
Describe how the following expression are obtained:
7xy + 5, x²y, 4x² – 5x
Solution:
(i) 7xy + 5, we first obtain xy, multiply it by 7 to get Ixy and add 5 to Ixy to get the expression.
(ii) x²y, we first obtain x² and multiply it by y.
(iii) 4x² – 5x, we first obtain x² and multiply it by 4 to get 4x². From 4x², we subtract 5x to finally arrive at 4x² – 5x.

Try These (Page 231)

Question 1.
What are the terms in the following expressions ? Show how the terms are formed. Draw a tree diagram for each expression:
8y + 3x², 7mn – 4, 2x²y.
Solution:
8y + 3x² : The above expression 8y + 3x² consists two terms 8y and 3x². The terms 8y is product of 8 and y. And the term 3x² is product of 3, x and x.

7mn – 4: The above expression 7mn – 4 consist two terms 7mn and -4. The term 7mn is product of 7, m and n and the term – 4 has only one factor, that is – 4.

2x2y: The above expression consist only one term 2x2y. The product of the term 2x2y is 2,x, 2 andy or2 xxx 2 xy.

Try These (Page 231)

Question 1.
Identify the co-efficients of the following expressions:
4x – 3y, a + b + 5, 2y + 5, 2xy.
Solution:

Expression	Terms	Co-efficient
4x – 3y	4x -3y	4 -3
a + b + 5	a b	1 1
2y + 5	2y	2
2xy	2xy	2

Try These (Page 233)

Question 1.
Group the like terms together from the following:
12x 12, – 25x, -25, -25y, 1,x, 12y, y.
Solution:
12x, – 25x, x are like terms.
– 25y, 12y, y are like terms.

Try These (Page 233)

Question 1.
Classify the following expressions as a monomial, a binomial or a trinomial: a, a + b, ab + a + b, ab + a + b – 5, xy + 5, 5x² – x + 2,4pq -3q + 5p, 7,4m -7n + 10, 4mn + 7.
Solution:
a is a monomial.
a + b is a binomial.
ab + a + b is a trinomial.
ab + a + b – 5 is not a trinomial, because it contains 4 terms.
So it is polynomial.
xy + 5 is a binomial.
5x² – x + 2 is trinomial.
4pq -3q + 5p is trinomial.
7 is monomial.
4m -7n + 10 is trinomial.
4mn + 7 is binomial.

Try These (Page 236)

Question 1.
Sarita’s father’s age is 5 years more than 3 times Sarita’s age. What is her father’s age ?
Solution:
Since, Sarita’s father’s age is 5 years (y) more than 3 times Sarita’s age.
Therefore, her father’s age = (3y + 5) years.

Question 2.
The length of a rectangular hall is 4 metres less than 3 times the breadth of the hall. What is the length, if the breadth is b metres ?
Solution:
Let the breadth of the hall be b metres. Since, its length is 4 metres less than 3 times the breadth of the hall.
∴ Length of the hall = (3b – 4) metres.

Try These (Page 238)

Question 1.
Add and subtract:
(i) m – n, m + n
(ii) mn + 5 – 2, mn + 3.
Solution:
(i) Adding (m – n) and (m + n) we have m -n + m + n = m + m = 2m
∴ The sum = 2m
Subtract: m – n – (m + n)
= m – n – m – n
= -n-n
= -2n
∴ The difference is -2n.

(ii) Adding mn + 5 – 2 and mn + 3, we have (mn + 5 – 2) + mn + 3
= mn + 5 – 2 + mn + 3
= (mn + mn) + (5 – 2 + 3)
= 2 mn + 6
∴ The sun = 2mn + 6.
Subtract : (mn + 3) from (mn + 5-2), we have
(mn + 5 – 2) – (mn + 3)
= mn + 5 – 2 – mn – 3
= 0 + 3 – 3 = 0
∴ The difference is 0.

Try These (Page 245)

Question 1.
Make similar pattern with basic figures as shown:

(The number of segments required to make the figure is given to the right. Also, the expression for the number of segments required to make n shapes is also given).
Solution: