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10th Grade > Mathematics

POLYNOMIALS MCQs

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Total Questions : 79 | Page 4 of 8 pages
Question 31. Which of the following graph represents a quadratic polynomial which has sum of its zeroes is zero?
  1.    A)
  2.    B)
  3.    C)
  4.    D)
 Discuss Question
Answer: Option D. -> D)
:
D
We know that, the values at whicha quadratic polynomial cuts the x-axis are its zeroes.
Option A: Polynomial cuts the x-axis at : -3, -2 ; sum of zeroes: -5
Option B: Polynomial cuts the x-axis at : 2, 3; sum of zeroes: 5
Option C: Polynomial cuts the x-axis at : 2, 3; sum of zeroes: 5
Option D: Polynomial cuts the x-axis at : -2, 2; sum of zeros: 0
Hence, the answer is D.
Question 32. The polynomial ax3+bx2+x6 has (x+2) as a factor and leaves a remainder 4 when divided by (x2). Find a and b.
  1.    0,2
  2.    0,4
  3.    2,4
  4.    2,2
 Discuss Question
Answer: Option A. -> 0,2
:
A
Let
p(x)=ax3+bx2+x6
By using factor theorem, (x+2) can be a factor of p(x)only when p(2)=0
p(2)=a(2)3+b(2)2+(2)6=0
8a+4b8=0
2a+b=2...(i)
Also when p(x) is divided by (x2) the remainder is 4.
p(2)=4
a(2)3+b(2)2+26=4
8a+4b+26=4
8a+4b=8
2a+b=2...(ii)
Adding equations (i)and (ii), we get
(2a+b)+(2a+b)=2+2
2b=4b=2
Putting b=2 in (i)we get
2a+2=2
2a=0a=0
Hence,
a=0andb=2
Question 33. The polynomials ax3+4x2+3x4 and x34x+a leave the same remainder when divided by (x3). Find the value of a.
  1.    −1
  2.    −2
  3.    −3
  4.    −4
 Discuss Question
Answer: Option A. -> −1
:
A
Given polynomials:
p(x)=ax3+4x2+3x4
q(x)=x34x+a
Using remainder theorm,​​​ t​he remainders when p(x)and q(x)are divided by (x3)are p(3) and q(3) respectively.
p(3)=a×(3)3+4×(3)2+3×34
p(3)=27a+41
q(3)=(3)34×3+a
q(3)=15+a
Given that the remainder is the same.
p(3)=q(3)
27a+41=15+a
26a=26
a=1
Question 34. Degree of a constant polynomial is _____.
  1.    1
  2.    0
  3.    Any natural number
  4.    Not defined
 Discuss Question
Answer: Option B. -> 0
:
B
As we know that any variable raised to the power of zero yields 1, aconstant polynomial can be represented as ax0, where, a is the constant and x is the variable of the polynomial. Thus the degree of a constant polynomial is 0.
Question 35. If a polynomial cuts the x-axis at 3 points and y-axis at 2 points, then the number of zeroes of the polynomial would be 
___
 Discuss Question

:
The point where the polynomial cuts the x-axis is the zero of the polynomial. Since the given polynomial cuts the x-axis at 3 points, the number of zeroes is 3.
Question 36. If x+x1=11, evaluate x2+x2.
  1.    119
  2.    120
  3.    121
  4.    122
 Discuss Question
Answer: Option A. -> 119
:
A
x+x1=11
(x+x1)2=112 [Squaring both the sides]
(x)2+(x1)2+2(x)(x1)=121
x2+x2+2=121 [(x)(x1)=x0=1]
x2+x2=1212=119
Question 37. If x100+2x99+k is divisible by (x+1), then the value of k is
  1.    1
  2.    -3
  3.    3
  4.    -2
 Discuss Question
Answer: Option A. -> 1
:
A
Since (x+1) is a factor, x=1will make the given expression zero.
(1)100+2×(1)99+k=012+k=0k=1
Question 38. If ax2+bx+c is a monomial in x , what can be said about a, b and c?
  1.    Atleast one of a, b and c is non - zero.
  2.    Only one among a, b and c is zero.
  3.    Only one among a, b and c is non - zero.
  4.    All three should be non - zero.
 Discuss Question
Answer: Option C. -> Only one among a, b and c is non - zero.
:
C
Since a monomial can containonly one term, only one of a, b and c can be non-zero to leave a single term.
Question 39. If xg+1xa is a polynomial, what could be the value of a?
  1.    only 1
  2.    any positive integer
  3.    any negative integer
  4.    any integer
 Discuss Question
Answer: Option C. -> any negative integer
:
C
For an expression to be a polynomial, the exponents of x should be whole numbers. The above expression can be written as xg+xa. For this to be a polynomial, a should be a whole number. This is possible if a is a negative integer or zero.
Question 40. Given the area of rectangle is A=25a235a+69. The length is given as (5a3).Find the width of the rectangle.
  1.    5a−3
  2.    5a−4
  3.    4a−5
  4.    a−4
 Discuss Question
Answer: Option B. -> 5a−4
:
B
Let ybe the width.
Given: Area=25a235a+69
We know that, area of a rectangle= Length×breadth
Hence,y×(5a3)=25a235a+69
y=(25a235a+69)÷(5a3)
By long division method,
5a35a23)¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯25a235a+6925a212a+¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯23a+6923a+69+¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯0
y=5a23Width of the rectangle =5a23

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