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
When numbers/literals are added or subtracted, they are called _________.
  • A
    identities
  • B
    terms
    Correct
  • C
    None of these
  • D
    expressions
2
Simplify: (x + y) (2x – 3y + z) – (2x – 3y)z
  • A
    \({\text{2}}{{\text{x}}^{\text{2}}}-{\text{ 3}}{{\text{y}}^{\text{2}}}-{\text{ xy }}-{\text{ xz }} + {\text{ 4yz}}\)
    Correct
  • B
    \({\text{2}}{{\text{x}}^{\text{2}}}-{\text{ 3}}{{\text{y}}^{\text{2}}}{\text{ }}-{\text{ 4yz}}\)
  • C
    \({\text{2}}{{\text{x}}^{\text{2}}}-{\text{ 3}}{{\text{y}}^{\text{2}}}-{\text{ xy }} + {\text{ 3yz}}\)
  • D
    None of these
3
if\(x + \frac{1}{x} = 6,find{\text{ }}{x^2} + \frac{1}{{{x^2}}}\)
  • A
    39
  • B
    None of these
  • C
    34
    Correct
  • D
    32
4
If\(x - \frac{1}{x} = 5\), find\({x^2} + \frac{1}{{{x^2}}}\)
  • A
    34
  • B
    20
  • C
    23
  • D
    27
    Correct
5
Which of the following is an expression?
  • A
    \(\frac{1}{4}\)
  • B
    7
  • C
    9ab +7
    Correct
  • D
    9
6
Which of the following is a trinomial?
  • A
    4x + y
  • B
    3x
  • C
    2x + 7
  • D
    7 – 3x + 4y
    Correct
7
Which of the following is like term as\({\text{3x}}{{\text{y}}^{\text{2}}}\)?
  • A
    \({\text{7x}}{{\text{y}}^{\text{2}}}\)
    Correct
  • B
    7xy
  • C
    7x
  • D
    \({\text{7}}{{\text{y}}^{\text{2}}}\)
8
Subtract 3x (x – 4y + 5z) from 4x (2x – 3y + 10z).
  • A
    25xz
  • B
    \({\text{5}}{{\text{x}}^{\text{2}}} + {\text{ 25xz}}\)
    Correct
  • C
    \({\text{5}}{{\text{x}}^{\text{2}}} + {\text{ 25xy}}\)
  • D
    \({\text{5}}{{\text{x}}^{\text{2}}}\)
9
n ( 4 + m) = 4n + ___
  • A
    4n
  • B
    nm
    Correct
  • C
    4mn
  • D
    4m
10
Using identity evaluate 297 \( \times \) 303.
  • A
    99999
  • B
    89991
    Correct
  • C
    79991
  • D
    None of these
11
Simplify: (1.5x – 4y)(1.5x + 4y +3) – 4.5x +12y
  • A
    \({{\text{x}}^{\text{2}}}-{\text{ 16}}{{\text{y}}^{\text{2}}}\)
  • B
    \({\text{2}}.{\text{25}}{{\text{x}}^{\text{2}}}--{\text{ 16}}{{\text{y}}^{\text{2}}}\)
    Correct
  • C
    None of these
  • D
    \({\text{2}}.{\text{25}}{{\text{x}}^{\text{2}}}-{\text{ }}{{\text{y}}^{\text{2}}}\)
12
If x + y = 12 and xy = 32, find the value of \({{\text{x}}^{\text{2}}} + {\text{ }}{{\text{y}}^{\text{2}}}\).
  • A
    80
    Correct
  • B
    70
  • C
    None of these
  • D
    60
13
(x – a (x + a) =?
  • A
    \({\text{x }} + {\text{ }}{{\text{a}}^{\text{2}}}\)
  • B
    \({\text{x }}--{\text{ }}{{\text{a}}^{\text{2}}}\)
  • C
    \({{\text{x}}^{\text{2}}}--{\text{ }}{{\text{a}}^{\text{2}}}\)
    Correct
  • D
    \({{\text{x}}^{\text{2}}} + {\text{ }}{{\text{a}}^{\text{2}}}\)
14
Which of the following is a trinomial?
  • A
    3x
  • B
    4x + y
  • C
    2x + 7
  • D
    3a + 4b + 5
    Correct
15
Which of the following is like term as\({\text{7}}{{\text{x}}^{\text{2}}}{{\text{y}}^{\text{2}}}\)?
  • A
    \({\text{7}}{{\text{y}}^{\text{2}}}\)
  • B
    7x
  • C
    7y
  • D
    \({\text{13}}{{\text{x}}^{\text{2}}}{{\text{y}}^{\text{2}}}\)
    Correct