NCERT solutions for class 8 maths chapter 9 Algebraic Expressions and Identities is prepared by academic team of Physics Wallah. We have prepared solutions for all exercise with importants questions of chapter 9. Given below is step by step solutions of all questions given in NCERT textbook for chapter-9. Read chapter 9 theory make sure you have gone through the theory part of chapter-9 from NCERT textbook and you have learned the formula of the given chapter. Physics Wallah prepared a detail notes and additional questions for class 8 maths with short notes of all maths formula of class 8 maths. do read these contents before moving to solve the exercise of NCERT chapter 9.
Question 1.
Identify the terms, their coefficients for each of the following expressions:
(i)
(ii) 1 + x + x²
(iii)
(iv) 3 - pq + qr -rp
(v)
+
- xy
(vi) 3 - pq + qr -rp
Solution :
(i) Terms:
and
Coefficient in
is 5 and in
is
-3
(ii) Terms: 1, x and x²
Coefficient of
and coefficient of
x²
is 1.
(iii) Terms:
and
z²
Coefficient in
is 4, coefficient of
is -4 and coefficient of
z²
is 1.
(iv) Terms: 3, -pq, qr and -rp
Coefficient of
-pq
is
-1,
coefficient of
qr
is 1 and coefficient of
-rp
is
(v) Terms:
and
-xy
Coefficient of
is
coefficient of
is
and coefficient of
-xy
is
-1.
(vi) Terms: 0.3a, -0.6ab and 0.5b
Coefficient of 0.3a is 0.3, coefficient of -0.6ab is -0.6 and coefficient of 0.5b is 0.5.
Question 2.
Classify the following polynomials as monomials, binomials, trinomials. Which polynomials do not fit in any of these three categories:
Solution :
(i) Since
contains two terms. Therefore it is binomial.
(ii) Since 1000 contains one terms. Therefore it is monomial.
(iii) Since
contains four terms. Therefore it is a polynomial and it does not fit in above three categories.
(iv) Since
contains three terms. Therefore it is trinomial.
(v) Since
contains two terms. Therefore it is binomial.
(vi) Since
contains three terms. Therefore it is trinomial.
(vii) Since
contains three terms. Therefore it is trinomial.
(viii) Since
contains two terms. Therefore it is binomial.
(ix) Since
contains four terms. Therefore it is a polynomial and it does not fit in above three categories.
(x) Since pqr contains one terms. Therefore it is monomial.
(xi) Since
contains two terms. Therefore it is binomial.
(xii) Since 2p + 2q contains two terms. Therefore it is binomial.
Question 3.
Add the following:
(i)
(ii)
(iii)
(iv)
Solution :
(i)
Hence the sum if 0.
Hence the sum is ab + ac + bc.
Question 4.
Solution :
Question 1.
Find the product of the following pairs of monomials:
(i)
(ii)
(iii)
(iv)
(iv) 4p ,0
Solution :
(i)
=
=
(ii)
=
=
(iii)
=
=
(iv)
=
=
(v)
=
= 0
Question 2.
Find the areas of rectangles with the following pairs of monomials as their lengths and breadths respectively:
Solution :
(i) Area of rectangle
=
=
sq. units
(ii) Area of rectangle
=
=
= 50mn sq. units
(iii) Area of rectangle =
=
=
sq. units
(iv) Area of rectangle =
=
=
sq. units
(v) Area of rectangle =
=
=
sq. units
Question 3.
Complete the table of products:
(i)
Solution :
(i)
Question 4.
Obtain the volume of rectangular boxes with the following length, breadth and height respectively:
(i)
(ii)
(iii)
(iv)
Solution :
(i) Volume of rectangular box
=
=
cubic units
(ii) Volume of rectangular box
=
=
cubic units
(iii) Volume of rectangular box
=
=
cubic units
(iv) Volume of rectangular box
=
=
cubic units
Question 5.
Obtain the product of:
(i)
(ii)
(iii)
(iv)
(v)
Solution :
(i)
=
(ii)
=
=
(iii)
=
(iv)
=
(v)
=
Question 1.
Carry out the multiplication of the expressions in each of the following pairs:
(i)
(ii)
(iii)
(iv)
(v)
Solution :
(i)
=
(ii)
=
(iii)
=
(iv)
=
(v)
=
= 0 + 0 + 0 = 0
Question 2.
Complete the table:
Solution :
Question 3.
Find the product:
(i)
(ii)
(iii)
(iv)
Solution :
(i)
=
(ii)
=
=
(iii)
=
=
(iv)
=
Question 4.
(a) Simplify:
and find values for
(i)
(ii)
(b) Simplify:
find its value for
(i)
(ii)
(iii)
Solution :
(a)
=
(i) For
=
= 108 – 45 + 3 = 66
(ii) For
=
=
=
(b)
=
(i) For a= 0,
=
= 0 + 0 + 0 + 5 = 5
(ii) For a = 1
=
= 1 + 1 + 1 + 5 = 8
(iii) For
=
=
=
=4
Question 5.
(a) Add:
and
(b) Add:
and
(c) Subtract:
from
(d) Subtract:
from
Solution :
(a)
=
=
(b)
+
=
=
=
(c)
=
=
=
(d)
=
=
=
=
=
=
NCERT Solutions for Class 8 Maths Exercise 9.4
Question 1.
Multiply the binomials:
(i)
and
(ii)
and
(iii)
and
(iv)
and
(v)
and
(vi)
and
Solution :
(i)
=
=
=
(ii)
=
=
=
(iii)
=
=
=
(iv)
=
=
(v)
=
=
=
=
(vi)
=
=
=
Question 2.
Find the product:
(i)
(ii)
(iii)
(iv)
Solution :
(i)
=
=
= 15 - x -2x²
(ii)
=
=
(iii)
=
=
(iv)
=
=
Question 3.
Simplify:
(i)
(ii)
(iii)
(iv)
(v)
(vi)
(vii)
(viii)
Solution :
(i)
=
=
=
(ii)
=
=
=
(iii)
=
=
(iv)
=
=
=
= 4ac
(v)
=
=
=
(vi)
=
=
(vii)
=
=
=
(viii)
=
=
=
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