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MATHS MCQ

Algebraic Expressions and Identities · ICSE STD 8 (ICSE - English Medium). 16 questions.

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16 questions · timed · auto-graded

MCQ 11 Mark
If the area of a rectangle is $24\left(x^2 y z+x y^2 z+x y z^2\right)$ and its length is $8\  x y z$, then its breadth is
  • ✓
    $3(x+y+z)$
  • B
    $3\ x y z$
  • C
    $3(x+y-z)$
  • D
    none of these
Answer
Correct option: A.
$3(x+y+z)$
In a rectangle
Area $=24\left(x^2 y z+x y^2 z+x y z^2\right)$
Length $=8 x y z$
Breadth $=\frac{24 x y z(x+y+z)}{8 x y z}=3( x + y + z )$
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MCQ 21 Mark
$96 \times 104$ is equal to
  • ✓
    $9984$
  • B
    $9974$
  • C
    $9964$
  • D
    none of these
Answer
Correct option: A.
$9984$
$96 \times 104$
$=(100-4)(100+4)$
$=(100)^2-(4)^2$
$=10000-16$
$=9984 $
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MCQ 31 Mark
$-50 x^3 y^2 z^2$ divided by $-5 x y z$ is equal to
  • A
    $10 x y z$
  • ✓
    $10 x^2 y z$
  • C
    $-10 x y z$
  • D
    $-10 x^2 y z$
Answer
Correct option: B.
$10 x^2 y z$
$\frac{-50 x^3 y^2 z^2}{-5 x y z}=10 x^2 y z $
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MCQ 41 Mark
$(102)^2-(98)^2$ is equal to
  • A
    $200$
  • B
    $400$
  • C
    $600$
  • ✓
    $800$
Answer
Correct option: D.
$800$
$(102)^2-(98)^2$
$=(102+98) \times(102-98)$
$=200 \times 4$
$=800$
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MCQ 51 Mark
If $x^2 + y^2 = 9$ and $xy = 8,$ then $x + y$ is equal to
  • A
    $25$
  • B
    $5$
  • C
    $-5$
  • ✓
    $\pm 5$
Answer
Correct option: D.
$\pm 5$
$x^2+y^2=9, x y=8$
$(x+y)^2=x^2+y^2+2 x y$
$=(9)^2+2 \times 8$
$=9+16=25$
$= \pm(5)$
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MCQ 61 Mark
If $x+\frac{1}{x}=2$, then $x^2+\frac{1}{x^2}$ is equal to
  • A
    $4$
  • ✓
    $2$
  • C
    $0$
  • D
    none of these
Answer
Correct option: B.
$2$
$x+\frac{1}{x}=2$
Squaring both sides,
$\left(x+\frac{1}{x}\right)^2=(2)^2$
$\Rightarrow x^2+\frac{1}{x^2}+2 \times x \times \frac{1}{x}=4$
$\Rightarrow x^2+\frac{1}{x^2}=4-2$
$\Rightarrow x^2+\frac{1}{x^2}=2$
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MCQ 71 Mark
$(x-1)(x+2)$ is equal to
  • A
    $2 x+3$
  • B
    $x^2+2 x+2$
  • ✓
    $x^2+3 x+2$
  • D
    $x^2+2 x+3$
Answer
Correct option: C.
$x^2+3 x+2$
$(x+1)(x+2)$
$=x^2+(1+2) x+1 \times 2$
$=x^2+3 x+2$
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MCQ 81 Mark
Volume of a rectangular box whose adjacent edges are $3 x^2 y, 4 y^2 z$ and $5 z^2 x$ respectively is
  • A
    $60 x y z$
  • B
    $60 x^2 y^2 z^2$
  • ✓
    $60 x^3 y^3 z^3$
  • D
    none of these
Answer
Correct option: C.
$60 x^3 y^3 z^3$
Volume $=3 x^2 y \times 4 y^2 z \times 5 z^2 x=60 x^3 y^{3} z^3 $
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MCQ 91 Mark
$3\  m \times\left(2\  m^2-5\  m n+4\  n^2\right)$ is equal to
  • A
    $6\  m^3+15\  m^2 n-12\  m n^2$
  • ✓
    $6\  m^3-15\  m^2 n+12\  m n^2$
  • C
    $6\  m^3-15\  m^2 n-12\  m n^2$
  • D
    $6\  m^3+15\  m^2 n+12\  m n^2$
Answer
Correct option: B.
$6\  m^3-15\  m^2 n+12\  m n^2$
$3\  m \times\left(2\  m^2-5\  m n+4\  n^2\right)$
$=6\  m^3-15\  m^2 n+12\  m n^2$
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MCQ 101 Mark
$\left(3 p^2 q r^3\right) \times\left(-4 p^3 q^2 r^2\right) \times\left(7 p q^3 r\right)$ is equal to
  • A
    $84 p^6 q^6 r^6$
  • ✓
    $-84 p^6 q^6 r^6$
  • C
    $84 p^6 q^5 r^6$
  • D
    $-84 p^6 q^5 r^6$
Answer
Correct option: B.
$-84 p^6 q^6 r^6$
$\left(3 p^2 q r^3\right) \times\left(-4 p^3 q^2 r^2\right) \times\left(7 p q^3 r\right)$
$=3(-4) \times 7 p^{2+3+1} \times q^{1+2+3} \times r^{3+2+1}$
$=-84 p^6 q^6 r^6$
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MCQ 111 Mark
$\frac{7}{5} x y-\frac{2}{3} x y+\frac{8}{9} x y$ is equal to
  • ✓
    $\frac{73}{45} x y$
  • B
    $-\frac{73}{45} x y$
  • C
    $x y$
  • D
    none of these
Answer
Correct option: A.
$\frac{73}{45} x y$
$\frac{7}{5} x y-\frac{2}{3} x y+\frac{8}{9} x y$
$=\frac{63 x y-30 x y+40 x y}{45}$
$=\frac{73}{45} x y$
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MCQ 121 Mark
$a(b -c) + b(c\  – a) + c(a – b)$ is equal to
  • A
    $ab + bc + ca$
  • ✓
    $0$
  • C
    $2(ab + bc + ca)$
  • D
    none of these
Answer
Correct option: B.
$0$
$a(b -c) + b(c – a) + c(a – b)$
$= ab – ac + bc – ab + ac – bc = 0 $
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MCQ 131 Mark
Degree of the polynomial $7x^2yz^2 + 6x^3y^2z^2 – 5x + 8y$ is
  • A
    $4$
  • B
    $5$
  • C
    $6$
  • ✓
    $7$
Answer
Correct option: D.
$7$
Degree of polynomial $7x^2yz^2 + 6x^3y^2z^2 -5x + 8y$ is $3 + 2 + 2 = 7$
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MCQ 141 Mark
Which of the following algebraic expressions is not a monomial?
  • A
    $3 x \times y \times z$
  • B
    $-5 pq$
  • C
    $8 m^2 \times n \div 31$
  • ✓
    $7 x \div y-z$
Answer
Correct option: D.
$7 x \div y-z$
$7 x \div y - z =\frac{7 x}{y}- z$
It is not monomial.
$($As it has two terms$)$
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MCQ 151 Mark
Which of the following algebraic expression is
  • A
    $3 x^2-2 x+7$
  • B
    $\frac{5 x^3}{2 x}+3 x^2+8$
  • ✓
    $3 x+\frac{2}{x}+7$
  • D
    $\sqrt{2} x^2+\sqrt{3} x+\sqrt{6}$
Answer
Correct option: C.
$3 x+\frac{2}{x}+7$
$3 x^2-2 x+7$ is not an algebraic expression. 
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MCQ 161 Mark
The literal coefficient of $-9xyz^2$ is
  • ✓
    $-9$
  • B
    $xy$
  • C
    $xyz^2$
  • D
    $-9xy$
Answer
Correct option: A.
$-9$
Literal co$-$efficient of $-9xyz^2$ is $-9$
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