Class 8 Algebraic Expressions And Identities CBSE Questions & Answers

Class 8 · Algebraic Expressions And Identities

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

Questions & Answers

1
x (x – 3) + 2 = ?
  • A
    None of these
  • B
    \({x^{\text{2}}}\) – 2x + 2
  • C
    \({x^{\text{2}}}\)– 3x + 2
    Correct
  • D
    \({x^{\text{2}}}\) – 5x + 3
2
3y (2y – 7) – 3 (y – 4) – 63 = ?
  • A
    6 \({y^{\text{2}}}\) – y – 51
  • B
    6 \({y^{\text{2}}}\) – 24y – 51
    Correct
  • C
    None of these
  • D
    \({y^{\text{2}}}\) – y – 51
3
Add 5m (3 – m) and 6 \({m^{\text{2}}}\) – 13m.
  • A
    \({m^{\text{2}}}\) – 2m
  • B
    None of these
  • C
    \({m^{\text{2}}}\) + 2m
    Correct
  • D
    \({m^{\text{2}}}\) + 5m
4
Add 4y (3 \({y^{\text{2}}}\) + 5y – 7) and 2 (\({y^{\text{3}}}\)– 4 \({y^{\text{2}}}\) + 5).
  • A
    14 \({y^{\text{3}}}\) + 12 \({y^{\text{2}}}\) – 28y
  • B
    14 \({y^{\text{3}}}\) + 12 \({y^{\text{2}}}\) – 28y + 10
    Correct
  • C
    14 \({y^{\text{3}}}\) + 12 \({y^{\text{2}}}\) – 10
  • D
    None of these
5
Subtract 3pq (p – q) from 2pq (p + q).
  • A
    None of these
  • B
    \(-{p^{\text{2}}}q + {\text{ 5}}p{q^{\text{2}}}\)
    Correct
  • C
    \(-{p^{\text{2}}}q\)
  • D
    \({\text{5}}p{q^{\text{2}}}\)
6
\(\left( {{\text{3}}a + {\text{ 4}}b} \right){\text{ }} \times {\text{ }}\left( {{\text{2}}a + {\text{ 3}}b} \right){\text{ }} = {\text{ }}?\)
  • A
    \({\text{6}}{a^{\text{2}}} + {\text{ 17}}ab + {\text{ 17}}{b^{\text{2}}}\)
  • B
    \({\text{6}}{a^{\text{2}}} + {\text{ 17}}ab\)
  • C
    None of these
  • D
    \({\text{6}}{a^{\text{2}}} + {\text{ 17}}ab + {\text{ 12}}{b^{\text{2}}}\)
    Correct
7
Multiply (x – 4) and (2x + 3).
  • A
    2 \({x^{\text{2}}}\) – 12
  • B
    \({\text{2}}{x^{\text{2}}}--{\text{ 5}}x-{\text{ 12}}\)
    Correct
  • C
    5x – 12
  • D
    None of these
8
Multiply (x – y) and (3x + 5y).
  • A
    \({\text{3}}{x^{\text{2}}} + {\text{ 2}}xy-{\text{ 7}}{y^{\text{2}}}\)
  • B
    None of these
  • C
    \({\text{5}}{x^{\text{2}}} + {\text{ 2}}xy-{\text{ 5}}{y^{\text{2}}}\)
  • D
    \({\text{3}}{x^{\text{2}}} + {\text{ 2}}xy-{\text{ 5}}{y^{\text{2}}}\)
    Correct
9
Multiply (a + 7) and (b – 5).
  • A
    None of these
  • B
    ab – 5a + 7b
  • C
    ab – 5a + 7b – 35
    Correct
  • D
    ab – 5a – 35
10
Multiply \(\left( {{a^{\text{2}}} + {\text{ 2}}{b^{\text{2}}}} \right)\) and (5a – 3b).
  • A
    \({\text{5}}{a^{\text{3}}}-{\text{ 3}}{a^{\text{2}}}b + {\text{ 1}}0a{b^{\text{2}}}\)
  • B
    None of these
  • C
    \({\text{5}}{a^{\text{3}}}-{\text{ 3}}{a^{\text{2}}}b-{\text{ 6}}{b^{\text{3}}}\)
  • D
    \({\text{5}}{a^{\text{3}}}-{\text{ 3}}{a^{\text{2}}}b + {\text{ 1}}0a{b^{\text{2}}}-{\text{ 6}}{b^{\text{3}}}\)
    Correct
11
Simplify (a + b) (2a – 3b + c) – (2a – 3b) c.
  • A
    2 \({a^{\text{2}}}\) – 3 \({b^{\text{2}}}\) – ab + 4bc – ac
    Correct
  • B
    2 \({a^{\text{2}}}\) – 3 \({b^{\text{2}}}\) – ab + 4bc
  • C
    2 \({a^{\text{2}}}\) – 3 \({b^{\text{2}}}\) – ab + ac
  • D
    None of these
12
(a + 1) (a +2) = ?
  • A
    \({a^{\text{2}}}\) + 5a + 2
  • B
    \({a^{\text{2}}}\) + 3a + 2
    Correct
  • C
    None of these
  • D
    \({a^{\text{2}}}\) + 3a + 5
13
Using the Identity find\({\left( {{\text{2}}x + {\text{ 3}}y} \right)^{\text{2}}}\).
  • A
    16 \({x^{\text{2}}}\) + 12xy + 9 \({y^{\text{2}}}\)
  • B
    4 \({x^{\text{2}}}\) + 12xy + 16 \({y^{\text{2}}}\)
  • C
    None of these
  • D
    4 \({x^{\text{2}}}\) + 12xy + 9 \({y^{\text{2}}}\)
    Correct
14
Using Identity, find \({\text{98}}{{\text{3}}^{\text{2}}}--{\text{ 1}}{{\text{7}}^{\text{2}}}\).
  • A
    966
  • B
    1000
  • C
    None of these
  • D
    966000
    Correct
15
Using Identity, find \({\text{194 }} \times {\text{ 2}}0{\text{6}}\).
  • A
    39964
    Correct
  • B
    38000
  • C
    None of these
  • D
    35988