Class 8 Factorisation CBSE Questions & Answers

Class 8 · Factorisation

This is Mathematics Class 8 Factorisation CBSE Questions & Answers. There are 15 questions in this test with each question having around four answer choices.

Questions & Answers

1
Factorise: \({{\text{a}}^{\text{2}}}-{\text{ }}{{\text{b}}^{\text{2}}}-{\text{ a }}-{\text{ b}}\)
  • A
    None of these
  • B
    (a + b)
  • C
    (a – b – 1)
  • D
    (a + b) (a – b – 1)
    Correct
2
Factorise: \({{\text{x}}^{\text{5}}}-{\text{ 16}}{{\text{x}}^{\text{3}}}\)
  • A
    (x – 4) (x + 4)
  • B
    \({{\text{x}}^{\text{3}}}\left( {{\text{x }}-{\text{ 4}}} \right){\text{ }}\left( {{\text{x }} + {\text{ 4}}} \right)\)
    Correct
  • C
    \({{\text{x}}^{\text{3}}}\left( {{\text{x }}-{\text{ 4}}} \right)\)
  • D
    \({{\text{x}}^{\text{3}}}\left( {{\text{x }} + {\text{ 4}}} \right)\)
3
Factorise: k – 7 + 7lm – lmk
  • A
    None of these
  • B
    (1 – lm)
  • C
    (k – 7)
  • D
    (1 – lm) (k – 7)
    Correct
4
Factorise: \({{\text{x}}^{\text{2}}}-{\text{ 11x }}-{\text{ 42}}\)
  • A
    (x + 3)
  • B
    (x – 14) (x + 3)
    Correct
  • C
    (x – 14)
  • D
    None of these
5
Factorise: \({\text{2y }}-{\text{ 32}}{{\text{y}}^{\text{5}}}\)
  • A
    \({\text{2y }}\left( {{\text{1 }} + {\text{ 4}}{{\text{y}}^{\text{2}}}} \right){\text{ }}\left( {{\text{1 }}-{\text{ 2y}}} \right){\text{ }}\left( {{\text{1 }} + {\text{ 2y}}} \right)\)
    Correct
  • B
    2y (1 – 2y) (1 + 2y)
  • C
    \({\text{2y }}\left( {{\text{1 }} + {\text{ 4}}{{\text{y}}^{\text{2}}}} \right)\)
  • D
    None of these
6
Factorise: \({\left( {{\text{2r }}-{\text{ 5}}} \right)^{\text{2}}} + {\text{ }}\left( {{\text{2r }}-{\text{ 5}}} \right)\)
  • A
    2 (2r – 5)
  • B
    2 (2r – 5) (r – 2)
    Correct
  • C
    (2r – 5) (r – 2)
  • D
    None of these
7
The H.C. F of the three terms \({\text{15}}{{\text{a}}^{\text{2}}}{{\text{b}}^{\text{2}}},{\text{ }} - {\text{2}}0{{\text{a}}^{\text{3}}}{\text{b}},{\text{ 1}}0{\text{a}}{{\text{b}}^{\text{2}}}\)is
  • A
    5a
  • B
    5ab
    Correct
  • C
    ab
  • D
    5
8
The H.C.F of \({\text{56}}{{\text{m}}^{\text{4}}},{\text{ 64}}{{\text{m}}^{\text{3}}},{\text{ }} - {\text{4}}0{{\text{m}}^{\text{2}}}{\text{n}},{\text{ 48}}{{\text{m}}^{\text{2}}}{{\text{n}}^{\text{2}}}\)is
  • A
    \({\text{7}}{{\text{m}}^{\text{2}}}{{\text{n}}^{\text{2}}}\)
  • B
    \({\text{8}}{{\text{m}}^{\text{2}}}\)
    Correct
  • C
    \({\text{8}}{{\text{m}}^{\text{2}}}{\text{n}}\)
  • D
    16m
9
\(\left( {{\text{4}}{{\text{a}}^{\text{2}}}-{\text{ 4ab }} + {\text{ }}{{\text{b}}^{\text{2}}}} \right){\text{ }} \div {\text{ }}\left( {{\text{2a }}-{\text{ b}}} \right)\)is the same as
  • A
    b
  • B
    (2a – b)
    Correct
  • C
    2a
  • D
    (2a + b)
10
\({\text{9}}{{\text{m}}^{\text{2}}} + {\text{ 12mn }} + {\text{ 4}}{{\text{n}}^{\text{2}}}\)is same as
  • A
    (3m + 2n)
  • B
    \({\left( {{\text{3m }} + {\text{ 2n}}} \right)^{\text{2}}}\)
    Correct
  • C
    (3m - 2n)
  • D
    \({\left( {{\text{3m }} - {\text{ 2n}}} \right)^{\text{2}}}\)
11
\({\text{121}}{{\text{a}}^{\text{2}}}-{\text{ 25}}\)is same as
  • A
    (11a – 5) (11a + 5)
    Correct
  • B
    (11a + 5)
  • C
    \({\left( {{\text{11a }} + {\text{ 5}}} \right)^{\text{2}}}\)
  • D
    (11a – 5)
12
The product of (a – 7) (a + 2) will be
  • A
    \({{\text{a}}^{\text{2}}}-{\text{ 5a }}-{\text{ 14}}\)
    Correct
  • B
    \({{\text{a}}^{\text{2}}} + {\text{ 9a }} + {\text{ 14}}\)
  • C
    None of these
  • D
    \({{\text{a}}^{\text{2}}} - {\text{ 14}}\)
13
Two numbers whose sum is (–2) and product is (–99) are
  • A
    None of these
  • B
    -11 and 9
    Correct
  • C
    -9 and 11
  • D
    -11 and -9
14
\({{\text{x}}^{\text{2}}} + {\text{ }}\left( {{\text{a }} + {\text{ b}}} \right){\text{x }} + {\text{ ab}}\) is same as
  • A
    (x + b)
  • B
    (x + a)
  • C
    (x + a) (x + b)
    Correct
  • D
    None of these
15
The factorization of \({{\text{x}}^{\text{2}}}--{\text{ 1}}0{\text{x }} + {\text{ 21}}\) is
  • A
    (x – 3) (x – 7)
    Correct
  • B
    (x + 3) (x – 7)
  • C
    (x + 3) (x + 7)
  • D
    (x – 3) (x + 7)