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
Simplify: \({\left( {{\text{4}}m + {\text{ 5}}n} \right)^{\text{2}}} + {\text{ }}{\left( {{\text{5}}m + {\text{ 4}}n} \right)^{\text{2}}}\)
  • A
    \({\text{41}}{m^{\text{2}}} + {\text{ 16}}00mn + {\text{ 41}}{n^{\text{2}}}\)
  • B
    \({\text{51}}{m^{\text{2}}} + {\text{ 8}}0mn + {\text{ 51}}{n^{\text{2}}}\)
  • C
    \({\text{41}}{m^{\text{2}}} + {\text{ 8}}0mn + {\text{ 41}}{n^{\text{2}}}\)
    Correct
  • D
    None of these
2
(a – b) (a + b) + (b – c) (b + c) + (c – a) (c + a) = ?
  • A
    0
    Correct
  • B
    a
  • C
    1
  • D
    ab
3
Using identity\(\left( {{\text{x }} - {\text{ a}}} \right){\text{ }}\left( {{\text{x }} + {\text{ a}}} \right){\text{ }} = {\text{ }}{{\text{x}}^{{\text{2}}}}--{\text{ }}{{\text{a}}^{\text{2}}}\) find\({{\text{6}}^{\text{2}}}--{\text{ }}{{\text{5}}^{\text{2}}}\).
  • A
    1
  • B
    22
  • C
    11
    Correct
  • D
    None of these
4
Find the product of (7x – 4y) and (3x - 7y).
  • A
    None of these
  • B
    \({\text{21}}{{\text{x}}^{\text{2}}}--{\text{ 61xy }} + {\text{ 2}}0{{\text{y}}^{\text{2}}}\)
  • C
    \({\text{2}}0{{\text{x}}^{\text{2}}}--{\text{ 61xy }} + {\text{ 28}}{{\text{y}}^{\text{2}}}\)
  • D
    \({\text{21}}{{\text{x}}^{\text{2}}}--{\text{ 61xy }} + {\text{ 28}}{{\text{y}}^{\text{2}}}\)
    Correct
5
Using suitable identity find (a + 3)(a + 2).
  • A
    None of these
  • B
    \({{\text{a}}^{\text{2}}} + {\text{ 5a }} + {\text{ 5}}\)
  • C
    \({{\text{a}}^{\text{2}}} + {\text{ 5a }} + {\text{ 6}}\)
    Correct
  • D
    \({{\text{a}}^{\text{2}}} + {\text{ 1}}0{\text{a }} + {\text{ 6}}\)
6
Using identity \({\left( {{\text{a }} + {\text{ b}}} \right)^{\text{2}}} = {\text{ }}{{\text{a}}^{\text{2}}} + {\text{ 2ab }} + {\text{ }}{{\text{b}}^{{\text{2}}}}\) find the value of\({\text{1}}0{{\text{3}}^{\text{2}}}.\)
  • A
    None of these
  • B
    10000
  • C
    10609
    Correct
  • D
    10909
7
Using identity \({\left( {{\text{a }}-{\text{ b}}} \right)^{\text{2}}} = {\text{ }}{{\text{a}}^{\text{2}}}-{\text{ 2ab }} + {\text{ }}{{\text{b}}^{\text{2}}}\) find the value of \({\text{9}}{{\text{8}}^{\text{2}}}\).
  • A
    9604
    Correct
  • B
    9000
  • C
    None of these
  • D
    9700
8
Using identity find\({\left( {{\text{2x }} + {\text{3}}} \right)^{\text{2}}}\).
  • A
    \({\text{16}}{{\text{x}}^{\text{2}}} + {\text{ 12x }} + {\text{ 9}}\)
  • B
    \({\text{4}}{{\text{x}}^{\text{2}}} + {\text{ 12x }} + {\text{ 9}}\)
    Correct
  • C
    None of these
  • D
    \({\text{4}}{{\text{x}}^{\text{2}}} + {\text{ 12x }} + {\text{ 1}}0\)
9
Subtract\({\text{7x }} - {\text{ 3}}{{\text{x}}^{\text{2}}}\) from\({\text{4x }} + {\text{ 8}}{{\text{x}}^{\text{2}}}\).
  • A
    None of these
  • B
    \({\text{13}}{{\text{x}}^{\text{2}}}--{\text{ 3x}}\)
  • C
    \({\text{11}}{{\text{x}}^{\text{2}}}--{\text{ 8x}}\)
  • D
    \({\text{11}}{{\text{x}}^{\text{2}}}--{\text{ 3x}}\)
    Correct
10
Using suitable identity find\({\left( {{\text{7x }} - {\text{ 3y}}} \right)^{\text{2}}}\).
  • A
    \({\text{49}}{{\text{x}}^{\text{2}}}--{\text{ 42xy}} + {\text{ 9}}{{\text{y}}^{\text{2}}}\)
    Correct
  • B
    \({\text{49}}{{\text{x}}^{\text{2}}}--{\text{ 49xy}} + {\text{ 9}}{{\text{y}}^{\text{2}}}\)
  • C
    None of these
  • D
    \({\text{49}}{{\text{x}}^{\text{2}}}--{\text{ 42xy}} + {\text{ 16}}{{\text{y}}^{\text{2}}}\)
11
Add \({\text{4}}{{\text{x}}^{\text{2}}} + {\text{ 2xy }}--{\text{ 4}}\) and \({\text{7}}{{\text{x}}^{\text{2}}}--{\text{ 3xy }} + {\text{ 4}}\).
  • A
    \({\text{11}}{{\text{x}}^{\text{2}}}--{\text{ 7xy}}\)
  • B
    \({\text{11}}{{\text{x}}^{\text{2}}}--{\text{ xy}}\)
    Correct
  • C
    \({\text{11}}{{\text{x}}^{\text{2}}}--{\text{ 6xy}}\)
  • D
    None of these
12
Find the product of \({\text{4x}},{\text{ 7}}{{\text{x}}^{\text{2}}},{\text{ }} - {\text{2x}}.\)
  • A
    None of these
  • B
    \( - {\text{56}}{{\text{x}}^{\text{4}}}\)
    Correct
  • C
    \( - {\text{56}}{{\text{x}}^{\text{2}}}\)
  • D
    \( - {\text{56}}{{\text{x}}^{\text{3}}}\)
13
Find the product of \(\left( {{{\text{x}}^{\text{2}}}--{\text{ }}{{\text{y}}^{\text{2}}}} \right)\left( {{\text{2x }} + {\text{ y}}} \right).\)
  • A
    \({\text{2}}{{\text{x}}^{\text{3}}} - {\text{ }}{{\text{y}}^{\text{3}}} + {\text{ 2x}}{{\text{y}}^{\text{2}}}\)
  • B
    None of these
  • C
    \({\text{2}}{{\text{x}}^{\text{3}}} - {\text{ }}{{\text{y}}^{\text{3}}} + {\text{ }}{{\text{x}}^{\text{2}}}{\text{y }}--{\text{ 2x}}{{\text{y}}^{\text{2}}}\)
    Correct
  • D
    \({\text{2}}{{\text{x}}^{\text{3}}} - {\text{ }}{{\text{y}}^{\text{3}}} + {\text{ }}{{\text{x}}^{\text{2}}}{\text{y}}\)
14
Simplify: \({\left( {{\text{xy }} + {\text{ yz}}} \right)^{\text{2}}}--{\text{ }}{\left( {{\text{xy }}--{\text{ yz}}} \right)^{\text{2}}}\)
  • A
    4xz
  • B
    4x
  • C
    \({\text{4x}}{{\text{y}}^{\text{2}}}{\text{z}}\)
    Correct
  • D
    \({\text{4x}}{{\text{y}}^{\text{2}}}\)
15
Using identity find the product of \(\left( {\frac{a}{2} + \frac{{3b}}{4}} \right)\left( {\frac{a}{2} + \frac{{3b}}{4}} \right)\)
  • A
    \({{\text{a}}^{\text{2}}}\)
  • B
    \({{\text{b}}^{\text{2}}}\)
  • C
    None of these
  • D
    \(\frac{{{a^2}}}{4} + \frac{{3ab}}{4} + \frac{{9{b^2}}}{{16}}\)
    Correct