Q1: The common factor of x2y2 and x3y3 is
(a) x2y2
(b) x3y3
(c) x2y3
(d) x3y2
Ans: (a)
x2y2 = x × x × y × y
x3y3 = x × x × x × y × y × y
Q2: The common factor of x3y2 and x4y is
(a) x43y2
(b) x4y
(c) x3y2
(d) x3y
Ans: (d)
x3y2 = x × x × x × y × y
x4y = x × x × x × x × y
Q3: The common factor of a2m4 and a4m2 is
(a) a4m4
(b) a2m2
(c) a2m4
(d) a4m2
Ans: (b)
a2m4 = a × a × m × m × m × m
a4m2 = a × a × a × a × m × m
Q4: The common factor of 2x, 3x3, 4 is
(a) 1
(b) 2
(c) 3
(d) 4
Ans: (a)
2x = 2 × x
3x3 = 3 × x × x × x
4 = 2 × 2
Hence the common factor is 1
Q5: The common factor of 10ab, 30bc, 50ca is
(a) 10
(b) 30
(c) 50
(d) abc
Ans: (a)
10ab = 2 × 5 × a × b
30bc = 2 × 3 × 5 × b × c
50ca = 2 × 5 × 5 × c × a
Q6: The common factor of 14a2b and 35a4b2 is
(a) a4b2
(b) 35a4b2
(c) 14a2b
(d) 7a2b
Ans: (d)
14a2b = 2 × 7 × a × a × b
35a4b2 = 5 × 7 × a × a × a × a × b × b
Q7: The common factor of 72x3y4z4, 120z2d4x4 and 96y3z4d4 is
(a) 96z3
(b) 120z3
(c) 72z3
(d) 24z2
Ans: (d)
72x3y4z4 = 2 × 2 × 2 × 3 × 3 × x × x × x × y × y × y × y × z × z × z × z.
120z2d4x4 = 2 × 2 × 2 × 3 × 5 × z × z × d × d × d × d × x × x × x × x
96y3z4d4 = 2 × 2 × 2 × 2 × 2 × 3 × y × y × z × z × z × z × d × d × d × d
Hence common factor is 2 x 2 x 2 x 3 = 24z2
Q8: The factorisation of 12a2b + 15ab2 is
a) 3ab (4a + 5b)
(b) 3a2b (4a + 5b)
(c) 3ab2 (4a + 5b)
(d) 3a2b2 (4a + 5b)
Ans: (a)
12a2b + 15ab2 = 3ab(4a + 5b)
Q9: The factorisation of x2yz + xy2z + xyz2 is
(a) xyz(x + y + z)
(b) x2yz(x + y + z)
(c) xy2z(x + y + z)
(d) xyz2(x + y + z)
Ans: (a)
x2yz + xy2z + xyz2
= xyz (x + y + z)
Q10: The factorisation of a (x + y + z) + b(x + y + z) + c(x + y + z) is
(a) (a + b + c)(x + y + z)
(b) (ab + bc + ca)(x + y + z)
(c) (xy + yz + zx)(a + b + c)
(d) none of these
Ans: (a)
a(x + y + z) + b(x + y + z) + c(x + y + z)
= (x + y + z) (a + b + c)
Q11: The factorisation of 6xy – 4y + 6 – 9x is
(a) (3x – 2)(2y – 3)
(b) (3x + 2)(2y – 3)
(c) (3x – 2)(2y + 3)
(d) (3x + 2)(2y + 3)
Ans: (a)
6xy – 4y + 6 – 9x
= 2y(3x – 2) – 3(- 2 + 3x)
= (3x – 2)(2y – 3)
Q12: The factorisation of x2 + xy + 2x + 2y is
(a) (x + 2)(x + y)
(b) (x + 2)(x – y)
(c) (x – 2)(x + y)
(d) (x – 2)(x – y)
Ans: (a)
x2 + xy + 2x + 2y
= x(x + y) + 2(x + y) = (x + 2) (x + y).
Q13: The factorisation of ab – a – b + 1 is
(a) (a – 1)(b – 1)
(b) (a + 1)(b + 1)
(c) (a – 1)(b + 1)
(d) (a + 1)(b – 1)
Ans: (a)
ab – a – b + 1
= a(b – 1) – 1(b – 1)
= (a – 1)(b – 1)
Q14: The factorisation of x2 + x + xy + y + zx + z is
(a) (x + y + z)(x + 1)
(b) (x + y + z)(x + y)
(c) (x + y + z)(y + z)
(d) (x + y + z)(z + x)
Ans: (a)
x2 + x + xy + y + zx + z
= x(x + 1) + y(x + 1) + z(x + 1)
= (x + 1)(x + y + z)
Q15: The factorisation of x2 + 8x + 16 is
(a) (x + 2)2
(b) (x + 4)2
(c) (x – 2)2
(d) (x – 4)2
Ans: (b)
x2 + 8x + 16
= (x)2 + 2 (x)(4) + (4)2 ((a + b)2
= a2 + 2ab + b2))
= (x + 4)2.
Q16: The factorisation of 36x2y2 – 1 is
(a) (6xy – 1)(6xy + 1)
(b) (6xy – 1)2
(c) (6xy + 1)2
(d) (6 + xy)2
Ans: (a)
36x2y2 – 1
= (6xy)2 – (1)2 ((a2 - b2)
= (a+b)(a-b))
= (6xy – 1)(6xy + 1)
Q17: The value of (0.68)2 – (0.32)2 is
(a) -1
(b) 0
(c) 1
(d) 0.36
Ans: (d)
(0.68 + 0.32) (0.68 – 0.32)
= 0.36.
Q18: The factorisation of 3x2 + 10x + 8 is
(a) (3x + 4)(x + 2)
(b) (3x – 4)(x – 2)
(c) (3x + 4)(x – 2)
(d) (3x – 4)(x + 2)
Ans: (a)
3x2 + 10x + 8
= 3x2 + 6x + 4x + 8
= 3x(x + 2) + 4(x + 2)
= (x + 2)(3x + 4)
Q19: The factorisation of 6x2 – 5x – 6 is
(a) (2x – 3)(3x + 2)
(b) (2x + 3)(3x + 2)
(c) (2x – 3)(3x – 2)
(d) (2x + 3)(3x – 2)
Ans: (a)
6x2 – 5x – 6
= 6x2 – 9x + 4x – 6
= 3x(2x – 3) + 2(2x – 3)
= (2x – 3)(3x + 2)
Q20: The quotient of 28x2 + 14x is
(a) 2
(b) 2x
(c) x
(d) x2
Ans: (b)
= 2x
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2. What are the different methods of factorisation in algebra? |
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