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NCERT solutions for class 8 maths chapter 12 Exercise 12.1 Factorisation

In this page we have NCERT solutions for class 8 maths chapter 12 Exercise 12.1 for Factorisation.This exercise has questions on finding common factors, Factorisation by regrouping terms. Hope you like them and do not forget to like , social share and comment at the end of the page.

NCERT solutions for class 8 maths chapter 12 Exercise 12.1

Question 1
Find the common factors of the given terms.
(i) 12x, 36
(ii) 2y, 22xy
(iii) 14 pq, 28 p²q²
(iv) 2x, 3x², 4
(v) 6 abc, 24ab², 12 a²b
(vi) 16 x³, – 4x², 32x
(vii) 10 pq, 20qr, 30rp
(viii) 3x² y³, 10x³ y²,6 x² y²z
Answer:
(i) We need to convert each of these terms in simple factors forms and then choose the common factors
12x =2×2×3×x
36=2×2×3×3
So common Factor are 2,2,3
And 2×2×3=12
(ii) 2y=2×y
22xy=2×11×y×x
So common factors are 2,y
And 2×y=2y
(iii) 14 pq= 2×7×p×q
28 p²q²=2×2×7×p×p×q×q
So common factors are 2,7,p,q
=14pq
(iv) 2x=2×x
3x²=3×x×x
4=2×2
There is no common factor other than unity, so common factor= 1
(v) 6abc=2×3×a×b×c
24ab²=2×2×2×3×a×b×b
12a²b=2×2×3×a×a×b
Common factors are 2, 3, a, b
=6ab
(vi) 16x³=2×2×2×2×x×x×x
-4x²=-2×2×x×x
32x=-2×2×2×2×2×x
Common factors are 2, 2, x
=4x
(vii) 10pq=-2×5×p×q
20qr=-2×2×5×q×r
30rp=-2×3×5×p×r
Common factors are 2,5
=10
(viii) 3x²y³=3×x×x×y×y×y
10x³y³=2×5×x×x×x×y×y×y
6x²y²z=-2×3×x×x×y×y×z
Common factors are x, x, y, y
=x²y²

Question 2
Factorize the following expressions.
(i) 7x – 42
(ii) 6p – 12q
(iii) 7a² + 14a
(iv) – 16 z + 20 z³
(v) 20 l² m + 30 a l m
(vi) 5 x² y – 15 xy²
(vii) 10 a² – 15 b² + 20 c²
(viii) – 4 a² + 4 ab – 4 ca
(ix) x² y z + x y²z + x y z²
(x) a x² y + b x y² + c x y z²
Answer
In these problem, we need to factorize each term and then find common factors to factorize the expression
(i) 7x-42
= (7×x) – (7×6)
=7(x-6)
(ii) 6p-12q
= (6×p) – (6×2q)
=6(p-2q)
(iii) 7a²+14a
=(7×a×a) + (2×7×a)
=7a(a+2)
(iv) -16z+ 20z³
=4z(5z²-4)
(v) 20 l² m + 30 a l m
=(2×2×5×l×m×l) + (2×3×5×a×l×m)
=2lm(10l+15a)
(vi) 5 x²y -15 xy²
=(5×x×x×y) + (5×3×x×y×y)
=5x(xy-3y²)
(vii) 10a² -15 b²+20c²
=(2×5×a×a) - (5×3×b×b) + (5×2×2×c×c)
=5(2a²-3b²+4c²)
(viii) -4a² +4a b-4ca
=(-4×a×a) +(4×b×a) - (4×c×a)
=-4a(a-b+c)
(ix) x²yz + xy²z +xyz²
=(x×x×y×z) +(x×y×y×z) +(x×y×z×z)
=xyz(x+y+z)
(x) ax²yz + bxy²z +cxyz²
=(x×x×y×z×a) +(x×y×y×z×b) +(x×y×z×z×c)
=xyz(ax+by+cz)

Question 3
Factorize
(i) x² + x y + 8x + 8y
(ii) 15 xy – 6x + 5y – 2
(iii) ax + bx – ay – by
(iv) 15 pq + 15 + 9q + 25p
(v) z – 7 + 7 x y – x y z
Answer
(i) x² + x y + 8x + 8y
= x(x+y) + 8(x+y)
=(x+y)(x+8)
(ii) 15 xy – 6x + 5y – 2
= 3x(5y-2) +1(5y-2)
=(3x+1)(5y-2)
(iii) ax + bx – ay – by
= x(a+b) –y(a+b)
=(a+b)(x-y)
(iv) 15 pq + 15 + 9q + 25p
=15pq+9q +25p+15
= 3q(5p+3) + 5(5p+3)
=(3q+5)(5p+3)
(v) z – 7 + 7 x y – x y z
=z-xyz-7+7xy
=z(1-xy)-7(1-xy)
=(z-7)(1-xy)

Summary

NCERT solutions for class 8 maths chapter 12 Exercise 12.1 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 NCERT solutions Factorisation Exercise 12.1 as pdf
This chapter 12 has total 3 Exercise 12.1,12.2,12.3 as per latest syllabus. Exercise 12.4 is the deleted exercise as per latest syllabus. This is the First exercise in the chapter.You can explore previous exercise of this chapter by clicking the link below

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