Polynomials MCQ: Answers and Explanation

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Jasmine Grover

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The name "polynomial" comes from the words "poly" (meaning many) and "nomial" (meaning phrase), so it means "many terms."

  • A polynomial is made up of solely added, subtracted, and multiplied terms.
  • ax² + bx + c is the form of a quadratic polynomial in x with real coefficients, where a, b, and c are real numbers with a = 0.
  • The degree of a polynomial refers to the variable's highest exponent in the polynomial. 2x² + 4 is an example where the degree is 2.
  • Linear, quadratic, and cubic polynomials have the degrees 1, 2, and 3 polynomials, respectively.
  • A polynomial can have terms with constants such as 5, -2, and others, as well as variables like x and y and exponents such as 2 in y².
  • Addition, subtraction, and multiplication can be used to combine these, but not division.
  • The x-coordinates of the locations where the graph of y = p(x) contacts the x-axis are the zeroes of polynomial p(x).
  • If α and β are the zeroes of the quadratic polynomial ax² + bx + c, then:

Polynomial formula

  • If α, β, γ are the zeroes of the cubic polynomial ax³ + bx² + cx + d = 0, then:

Polynomial formula

  • Zeroes, also known as α, β, γ, follow the rules of algebraic identities, i.e.,

(α + β)² = α² + β² + 2αβ

∴(α² + β²) = (α + β)² – 2αβ

  • If p(x) and g(x) are any two polynomials with g(x) = 0, then p(x) = g(x) * q + r is the division algorithm:

Dividend = Divisor x Quotient + Remainder

The video below explains this:

Polynomials Detailed Video Explanation:


Question 1: If the zeroes of the quadratic polynomial ay² + by + c, c ≠ 0 are equal, then

  1. c and b have opposite signs
  2. c and a have opposite signs
  3. c and b have the same signs
  4. c and a have the same signs

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Answer: (d) c and a have the same signs

Explanation: Discriminant will be equal to zero for equal roots:

b² - 4ac = 0

b² = 4ac

ac = b²/4

ac > 0 (square of any number cannot be negative)

Question 2: If the sum of zeroes of the quadratic polynomial 3x² – kx + 6 is 3, then the value of k is:

  1. 4
  2. 5
  3. 7
  4. 9

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Answer: (d) 9

Explanation: Here a = 3, b = -k, c = 6

Sum of the zeroes, (α + β) = -b/a = 3 …..(given)

⇒ −(−k)/3 = 3

⇒ k = 9

Question 3: The degree of the polynomial, x5 – 2x2 + 2 is:

  1. 2
  2. 4
  3. 1
  4. 5

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Answer: (d) 5

Explanation: In every polynomial, the highest power of the variable is called a degree.

Question 4: If p(x) is a polynomial of degree one and p(y) = 0, then y is said to be:

  1. Zero of p(x)
  2. Value of p(x)
  3. Constant of p(x)
  4. None of the above

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Answer: (a) Zero of p(x)

Explanation: Let p(x) = mx + n

Put x = y

p(y) = my + n = 0

So, y is zero of p(x).

Question 5: A polynomial's zeros can be represented graphically. The number of polynomial zeros equals the number of points on the graph of the polynomial:

  1. Intersects y-axis
  2. Intersects x-axis
  3. Intersects y-axis or x-axis
  4. None of the above

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Answer: (b) Intersects x-axis

Explanation: The number of zeroes of a polynomial is equal to the number of points where the graph of polynomial intersects the x-axis.

Read Also: 

Question 6: A polynomial of degree p has:

  1. Only one zero
  2. At least p zeroes
  3. More than p zeroes
  4. At most p zeroes

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Answer: (d)

Explanation: A polynomial's maximum number of zeroes equals the polynomial's degree.

Question 7: If α and β are the zeroes of a polynomial such that α + β = -6 and αβ = 5, then the polynomial is:

  1. x² + 6x + 5 = 0
  2. x² + 6x - 5 = 0
  3. x² - 6x + 5 = 0
  4. x² - 6x - 5 = 0

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Answer: (a) x² + 6x + 5 = 0

Explanation: Quadratic polynomial is x² – Sx + P = 0, where S is the sum and P is the product

⇒ x² – (-6)x + 5 = 0

⇒ x² + 6x + 5 = 0

Question 8: Zeros of p(x) = x² - 27 are:

  1. ± 3√3
  2. ± 9√3
  3. ± 7√3
  4. None of the above

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Answer: (a)

Explanation: x² - 27 = 0

x² = 27

x = √27

x = ±3√3

Question 9: The quadratic polynomial whose zeroes are 3 + √2 and 3 – √2 is:

  1. x² – 6x - 7
  2. x² + 6x + 7
  3. x² – 6x + 7
  4. x² + 6x - 7

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Answer: (c) x² – 6x + 7

Explanation: S is the sum of zeroes and P is the product of zeroes: 

S = (3 + √2) + (3 – √2) = 6

P = (3 + √2) x (3 – √2) = (3)² – (√2)² = 9 – 2 = 7

So, Quadratic polynomial = x² – Sx + P = x² – 6x + 7

Question 10: If a quadratic polynomial's discriminant, D, is greater than zero, the polynomial has:

  1. two real and equal roots
  2. two real and unequal roots
  3. imaginary roots
  4. no roots

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Answer: (b) two real and unequal roots

Explanation: If the discriminant of a quadratic polynomial, D > 0, then the polynomial has two real and unequal roots.


Also Read:

CBSE X Related Questions

1.
Check whether \(6n\) can end with the digit \(0\) for any natural number \(n\).

      2.
      An umbrella has 8 ribs which are equally spaced (see Fig. 11.10). Assuming umbrella to be a flat circle of radius 45 cm, find the area between the two consecutive ribs of the umbrella.
      An umbrella has 8 ribs which are equally spaced

          3.

          The following frequency distribution gives the monthly consumption of electricity of 68 consumers of a locality. Find the median, mean and mode of the data and compare them

          Monthly consumption 
          (in units)

           Number of consumers

          65 - 85 

          4

          85 - 105

          5

          105 - 125

          13

          125 - 145

          20

          145 - 165

          14

          165 - 185

          8

          185 - 205

          4

              4.

              The lengths of 40 leaves of a plant are measured correct to the nearest millimetre, and the data obtained is represented in the following table :

              Length (in mm)

              Number of leaves

              118 - 126

              3

              127 - 135 

              5

              136 - 144

              9

              145 - 153

              12

              154 - 162

              5

              163 - 171

              4

              172 - 180

              2

              Find the median length of the leaves. 
              (Hint : The data needs to be converted to continuous classes for finding the median, since the formula assumes continuous classes. The classes then change to 117.5 - 126.5, 126.5 - 135.5, . . ., 171.5 - 180.5.)

                  5.
                  A 1.5 m tall boy is standing at some distance from a 30 m tall building. The angle of elevation from his eyes to the top of the building increases from 30° to 60° as he walks towards the building. Find the distance he walked towards the building.

                      6.

                      Solve the following pair of linear equations by the substitution method. 
                      (i) x + y = 14 
                          x – y = 4   

                      (ii) s – t = 3 
                          \(\frac{s}{3} + \frac{t}{2}\) =6 

                      (iii) 3x – y = 3 
                            9x – 3y = 9

                      (iv) 0.2x + 0.3y = 1.3 
                           0.4x + 0.5y = 2.3 

                      (v)\(\sqrt2x\) + \(\sqrt3y\)=0
                          \(\sqrt3x\) - \(\sqrt8y\) = 0

                      (vi) \(\frac{3x}{2} - \frac{5y}{3}\) =-2,
                          \(\frac{ x}{3} + \frac{y}{2}\) = \(\frac{ 13}{6}\)

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