Notes
Worksheets
Ncert Solutions
In this page we have Important questions for Algebraic Expressions and Identities Class 8 Maths Chapter 9 . Hope you like them and do not forget to like , social share
and comment at the end of the page.
Question 1
Identify the terms, their coefficients for each of the following expressions.
(i)xyz
2 + 3xy
(ii)1 - x -2x
2
(iii)4p
2q
2 - 4p
2q
2r
2+ r
2
(iv)4 - xy + yz - xz
(v) (x/4) - (y/5) -y
(vi)1.3a - 2.6ab + 1.5b
Solution
i) Terms xyz2, 3xy coefficients 1,3
ii)Terms 1,-x,-2x2 Coefficients 1, -1,-2
iii)Terms 4p2q2,-4p2q2r2,r2 Coefficients 4,-4,1
iv) Terms 4,-xy,yz,-xz Coefficients 4,-1,1,-1
v) Terms x/4, -y/5 ,-y Coefficients 1/4,-1/5,-1
vi) Terms 1.3a,-2.6ab,1.5b Coefficients 1.3,-2.6 ,1.5
Question 2
Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories?
a)x
2 + y
2
b)1000-x
c)x + x
2+ x
3 + x
4 + x
5
d)8 - y -5x
e) 2y -3y
2
f) 2y - 3y+ 4y
3
g) 5x -8y + 3xy
h) 4 -15z
2
i) ab + bc + cd + da+ 2ab
j) pqr+2pq+5pqr
k) p
2q + pq
2
l) 2p + 2q+1
Solution
a)x2 + y2: Binomial
b)1000-x:Binomial
c)x + x2+ x3 + x4 + x5:polynomial
d)8 - y -5x:Trinomial
e) 2y -3y2:Binomial
f) 2y - 3y+ 4y3:Trinomial
g) 5x -8y + 3xy:Trinomial
h) 4 -15z2:Binomial
i) ab + bc + cd + da+ 2ab:polynomial
j) pqr+2pq+5pqr:Trinomial
k) p2q + pq2:Binomial
l) 2p + 2q+1:Trinomial
Question 3
Add the following.
(i) ab - bc+ ac, bc - ca+ ab, ca - ab-2bc
(ii)p - q + pq, q - r + qr, r - p + pr , p+q+r
(iii)2p
2q
2- 3pq + 4, 5 + 7pq - 3p
2q
2 ,4p
2q
2 + 10pq
(iv)a
2+ b
2, b
2+ c
2, c
2+ a
2, 2ab + 2bc + 2ac
Solution
i) ab - bc+ ac + bc - ca+ ab +ca - ab-2bc=ab-2bc+ac
ii)p - q + pq + q - r + qr + r - p + pr + p+q+r=p+q+pq+r+qr+pr
iii)2p2q2- 3pq + 4 + 5 + 7pq - 3p2q2 + 4p2q2 + 10pq=3p2q2+14pq+9
iv) a2+ b2+ b2+ c2+ c2+ a2+ 2ab + 2bc + 2ac=2(a2+ b2+c2+ab+bc+ac)
Question 4.
(a) Subtract 8a - 7ab + 3b - 20 from 20a - 9ab + 5b - 20
(b) Subtract 3pq + 5qr - 7pr+1 from -4pq +2qr - 2pr + 5pqr+1
(c) Subtract 4p
2q - 4pq - 5pq
2 - 8p + 7q - 18
from 18 - 3p - 11q + 5pq - 2pq
2+ 5p
2q
Solution
While subtracting, we need to remember signs are reversed after –sign once bracket is opened
ie. + becomes - and - becomes +
Let solve the below question keeping that in mind
a) 20a - 9ab + 5b - 20 -(8a - 7ab + 3b - 20)=20a - 9ab + 5b - 20-8a +7ab-3b+20 =12a+2b -2ab
b) -4pq +2qr - 2pr + 5pqr+1 -( 3pq + 5qr - 7pr+1 )=-4pq +2qr - 2pr + 5pqr+1 -3pq-5qr+7pr-1=-7pq -3qr+5pr+5pqr
c) 18 - 3p - 11q + 5pq - 2pq2+ 5p2q -(4p2q - 4pq - 5pq2 - 8p + 7q - 18)= 18 - 3p - 11q + 5pq - 2pq2+ 5p2q -4p2q+4pq +5pq2+8p-7q+18=36-3p-18q+9pq+3pq2+5p2q -4p2q
Question 5
What are the coefficient of each term in the below expression?
4p
2q
2 + 4p
2q
2r
2 - r
2 +5
a)4,4,-1,5
b)4,4,1,5
c) 4,4r
2 ,-r
2, 5
d) None of these
Solution
Answer is (a)
Question 6
The product of a monomial and trinomial will be a
a)monomial
b)trinomial
c)binomial
d) None of these
Solution
Answer is (b)
Question 7
The exponents of a variable term in the polynomial is a
a) integers
b)negative integers
c) positive integers
d) non -negative integers
Solution
Answer is (d)
Question 8
The expression pqr +rqp+qpr is a
a) Monomial
b)trinomial
c) binomial
d) none of these
Solution
Answer is (b)
Download Important questions for Algebraic Expressions and Identities as pdf
link to this page by copying the following text
Class 8 Maths
Class 8 Science
