PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1

Punjab State Board PSEB 8th Class Maths Book Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 Textbook Exercise Questions and Answers.

PSEB Solutions for Class 8 Maths Chapter 9 Algebraic Expressions and Identities Ex 9.1

1. Identify the terms, their coefficients for each of the following expressions:

(i) 5xyz2 – 3zy
(ii) 1 + x + x2
(iii) 4x2y2 – 4x2y2z2 + z2
(iv) 3 – pq + qr – rp
(v) \(\frac{x}{2}+\frac{y}{2}\) – xy
(vi) 0.3a – 0.6ab + 0.5b
Solution:

Terms Coefficient of terms
(i) 5 xyz2
-3zy
5
– 3
(ii) 1
x
x2
1
1
1
(iii) 4x2y2
– 4x2y2z2
z2
4
-4
1
(iv) 3
– pq
qr
– rp
3
– 1
1
– 1
(v) \(\frac {x}{2}\)
\(\frac {y}{2}\)
– xy
\(\frac {1}{2}\)
\(\frac {1}{2}\)
– 1
(vi) 0.3 a
– 0.6ab
0.5b
0.3
– 0.6
0.5

PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1

2. Classify the following polynomials as monomials, binomials, trinomials. which polynomials do not fit in any of these three categories?
x + y, 1000, x + x2 + x3 + x4, 7 + y + 5x, 2y – 3y2, 2y – 3y2 + 4y3, 5x – 4y + 3xy, 4z – 15z2, ab + bc + cd + da, pqr, p2q + pq2, 2p + 2q.
Solution:

Monomials Binomials Trinomials
1000
pqr
x + y
2y – 3y2
4z – 15y2
p2q +pq2
2p + 2q
7 + y + 5x
2y – 3y2 + 4y3
5x – 4y + 3xy

Following polynomials do not fit in any catagories:
x + x2 + x3 + x4 [∵ Polynomial has 4 terms] ab + bc + cd + da [∵ Polynomial has 4 terms]

3. Add the following:

Question (i)
ab – bc, bc – ca, ca – ab
Solution:
To add, let us arrange like terms one below the other.
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 1

PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1

Question (ii)
a – b + ab, b – c + bc, c – a + ac
Solution:
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 2

Question (iii)
2p2q2 – 3pq + 4, 5 + 7pq – 3p2q2
Solution:
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 3

Question (iv)
l2 + m2, m2 + n2, n2 + l2, 2lm + 2mn + 2nl
Solution:
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 4

PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1

4.

Question (a)
Subtract 4a – 7ab + 3b + 12 from 12a – 9ab + 5b – 3
Solution:
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 5

Question (b)
Subtract 3xy + 5yz – 7zx from 5xy – 2yz – 2zx + 10xyz
Solution:
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 6

PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1

Question (c)
Subtract 4p2q – 3pq + 5pq2 – 8p + 7q – 10 from 18 – 3p – 11q + 5pq – 2pq2 + 5p2q
Solution:
PSEB 8th Class Maths Solutions Chapter 9 Algebraic Expressions and Identities Ex 9.1 7

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