In this page we have Class 8 Maths Exercise 9.3 Solutions for
Algebraic Expressions and Identities. This exercise has questions about multiplication of polynomials like mononial to binomial and mononial to Trinomial. Hope you like them and do not forget to like , social share
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Class 8 Maths Exercise 9.3 Solutions
Question 1
Carry out the multiplication of the expressions in each of the following pairs.
(i) 4p, q + r
(ii) ab, a - b
(iii) a + b, 7a²b²
(iv) a
2- 9, 4a
(v) pq + qr + rp, 0
Answer:
- 4p(q + r) = 4pq + 4pr
- ab(a - b) = a2b - ab2
- (a + b) (7a2b2) = 7a3b2 + 7a2b3
- (a2 - 9)(4a) = 4a3 - 36a2
- (pq + qr + rp) x 0 = 0
Question 2
Complete the table.
Answer:
(i) a(b + c + d) = ab + ac + ad
(ii) (x + y – 5) 5xy= 5x
2y + 5xy
2 -25xy
(iii)p(6p
2– 7p + 5)=6p
3 -7p
2 +5p
(iv) 4p
2q
2(p
2 - q
2)=4p
4q
2 -4p
2q
4
(v) (a + b + c)abc= a
2bc + ab
2c + abc
2
Question 2
Find the product.
(i) a
2 x (2a
22) x (4a
26)
(ii) (2xy/3) ×(-9x
2y
2/10)
(iii) (-10pq
3/3) ×(6p
3q/5)
(iv) x (x
2) x (x
3) x (x
8)
Answer:
We will use the below property extensively in above questions
am x an x ao = am+n+o
(i) As you know
So, we get
a2 x (
2a22) x (
4a26) =
8a48
(ii) (2xy/3) ×(-9x
2y
2/10)
=(-3x3y3/5)
(iii) (-10pq
3/3) ×(6p
3q/5)
=(-4p4q4)
(iv)( x) x (x
2) x (x
3) x (x
8)
=
x14
Question 3
(a) Simplify 3x (4x - 5) + 3 and find its values for (i) x = 3 (ii) x =1/2
(b) Simplify
a (a2+ a + 1) + 5 and find its value for (i)
a = 0, (ii)
a = 1 (iii)
a = - 1.
Answer
(a)
(i) Putting x=3 in the equation we get
12x
2 - 15x + 3
=108-45+3 = 66
(ii) putting x=1/2 in the equation we get
$12 \times \frac {1}{2} - \frac {15}{2} + 3 =3 - \frac {15}{2} -3=\frac {-3}{2}$
(b)
a(a
2a+1)
=a
3+a
2+a
(i) putting a= 0 in the equation we get
0
3+0
2+0=0
(ii) putting a=1 in the equation we get
1
3 + 1
2 + 1 = 1 + 1 + 1 = 3
(iii) Putting a = -1 in the equation we get
-1
3+1
2 -1 = -1 + 1 + 1 = 1
Question 5
(a) Add:
p ( p - q), q ( q - r) and r ( r - p)
(b) Add:
2x (z - x - y) and
2y (z - y - x)
(c) Subtract:
3l (l - 4 m + 5 n) from
4l ( 10 n - 3 m + 2 l )
(d) Subtract:
3a (a + b + c ) - 2 b (a - b + c) from
4c ( - a + b + c )
Answer:
(a) (p
2 - pq) + (q
2 - qr) + (r
2 - pr)
= p
2 + q
2 + r
2 - pq - qr - pr
(b) (2xz - 2x
2 - 2xy) + (2yz - 2y
2 - 2xy)
= 2xz - 4xy + 2yz - 2x
2 - 2y
2
(c) (40ln - 12lm + 8l
2) - (3l
2 - 12lm + 15ln)
= 40ln - 12lm + 8l
2 - 3l
2 - 12lm + 15ln
= 55ln - 24lm + 5l
2
(d) = (-4ac + 4bc + 4c
2) - (3a
2 + 3ab + 3ac)
= -4ac + 4bc + 4c
2 - 3a
2 - 3ab - 3ac
= -7ac + 4bc + 4c
2 - 3a
2 - 3ab
Summary
- Class 8 Maths Exercise 9.3 Solutions has been prepared by Expert with utmost care. If you find any mistake.Please do provide feedback on mail. You can download the solutions as PDF in the below Link also
Download Class 8 Maths Exercise 9.3 as pdf
- This chapter 9 has total 5 Exercise 9.1 ,9.2 ,9.3 ,9.4 and 9.5. This is the Third exercise in the chapter.You can explore previous exercise of this chapter by clicking the link below
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