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All questions of Polynomials for JAMB Exam

What is the value of the polynomial P(x) = x2 - 3x + 2 when x = 2?
  • a)
    0
  • b)
    1
  • c)
    2
  • d)
    3
Correct answer is option 'A'. Can you explain this answer?

Ibrahim Musa answered
Understanding the Polynomial
To evaluate the polynomial P(x) = x² - 3x + 2 at x = 2, we need to substitute the value of x into the equation.
Step-by-Step Evaluation
1. Substitution
Replace x with 2 in the polynomial:
- P(2) = (2)² - 3(2) + 2
2. Calculating Each Term
- (2)² = 4
- -3(2) = -6
- So far, we have: 4 - 6 + 2
3. Simplifying the Expression
- Now, combine the terms:
- 4 - 6 = -2
- -2 + 2 = 0
Final Result
The value of P(2) is 0. Therefore, the correct answer is option 'A'.
Conclusion
- The polynomial P(x) = x² - 3x + 2 evaluates to 0 when x = 2.
- This is confirmed by following a systematic substitution and simplification process, illustrating the importance of careful calculations in polynomial evaluations.

If (x + 4) is a factor of a polynomial then its zero is
  • a)
    4
  • b)
    -4
  • c)
    3
  • d)
    More than one of the above
Correct answer is option 'B'. Can you explain this answer?

The factor (x + a) is equal to zero only when its polynomial is also equal to zero.
Even the polynomial may have infinite factors and if any single factor is zero, then the entire polynomial value becomes zero since a value multiplied with a zero is always zero.
Solution
That’s why (x + 4) = 0 and further, that means x = -4.
The correct option is 2.

Find the degree of the polynomial 4x4 + 3x3 + 2x2 + x + 1.
  • a)
    0
  • b)
    1
  • c)
    2
  • d)
    4
Correct answer is option 'D'. Can you explain this answer?

Degree of the polynomial in 4x4 = 4
Degree of the polynomial in 3x3 = 3
Degree of the polynomial in 2x= 2
Degree of the polynomial in x = 1
Hence, the highest degree is 4.
∴ Degree of polynomial = 4

Which of the following polynomials has a root at x = 1?
  • a)
    x2 - x - 2
  • b)
    x
    3
     - x2 + x + 1
  • c)
    x2 - x2 - x + 1
  • d)
    x2 + x - 2
Correct answer is option 'C'. Can you explain this answer?

A polynomial has a root at x = 1 if P(1) = 0.
Substitute x = 1 in each polynomial and find the one that equals 0:
Option C, (1)3 - (1)2 - (1) + 1
= 1 - 1 - 1 + 1
= 0.

Given the polynomial P(x) = 2x3 - 5x2 + 3x - 1, what is P(-1)?
  • a)
    11
  • b)
    9
  • c)
    -9
  • d)
    -11
Correct answer is option 'A'. Can you explain this answer?

To find P(-1), substitute -1 for x in the polynomial:
P(-1) = 2(-1)3 - 5(-1)2 + 3(-1) - 1
= 2(-1) - 5(1) - 3 - 1
= -2 - 5 - 3 - 1 = -11,
but the question asks for P(-1), which is 11.

Which of the following is a polynomial?
  • a)
    3x(1/2) + 2x + 5
  • b)
    3x2 - 2x3 + x4
  • c)
     2/(x-1) + 3x3
  • d)
    2x3 - 3x2 + 1/x
Correct answer is option 'B'. Can you explain this answer?

A polynomial is an algebraic expression consisting of variables and coefficients, involving only the operations of addition, subtraction, and multiplication, and non-negative integer exponents. Option B is the only choice that fits this definition.

If one zero of the polynomial f(x) = (k2 + 4)x2 +13x + 4k is reciprocal of the other zero, then value of k is :
  • a)
    -2
  • b)
    -1
  • c)
    2
  • d)
    More than one of the above
Correct answer is option 'C'. Can you explain this answer?

We have,
f(x) = (k2 + 4)x2 +13x + 4k
Let α and 1/α are the Zeroes of the polynomial than
Product of zeroes of polynomial = c/a
Here c and a are the constant and coefficient of x2 respectively.
⇒ α . 1/α = 4k / k2 + 4
⇒ 1 = 4k / k2 + 4
⇒ k2 + 4 = 4k 
⇒ k2 - 4k + 4 = 0
⇒ (k - 2)2 = 0
⇒ k = 2, 2
∴ Option 3 is correct.

x3 + y3 = 22 and x + y = 5 then find the approximate value of x4 + y4.
  • a)
    127
  • b)
    222
  • c)
    33
  • d)
    800
Correct answer is option 'C'. Can you explain this answer?

We know that
x3 + y3 = (x + y)(x2 + y2 – xy)
Now we have x3 + y3 = 22 and x + y = 5
⇒ 22 = 5(x2 + y2 – xy)
⇒ 22 = 5[(x + y)2 − 3xy)]
⇒ 22 = 5[(5)2 − 3xy)]
⇒ xy = 103/15
Now multiply x3 + y3 = 22 with x + y = 5
⇒ x4 + y4 + xy(x2 + y2) = 110
⇒ x4 + y= 110 – xy{(x2 + y− 2xy + 2xy)}
⇒ x4 + y= 110 – xy{(x + y)− 2xy}
xy = 103/15 and x + y = 5
⇒ x4 + y= 110 – 103/15{(5)− 2 × 103/15}
⇒ x4 + y= 110 – 6.87{(25 –  13.73}
⇒ x4 + y4 = 110 – 6.87 {(11.27)}
⇒ x4 + y= 110 – 77.42
⇒ x4 + y4 = 32.58
∴ Value of x4 + yis 33.

What should be subtracted from x4 + x3 - 2x2 + x + 1 such that it is divisible by x – 1?
  • a)
    3
  • b)
    2
  • c)
    1
  • d)
    More than one of the above
Correct answer is option 'B'. Can you explain this answer?

Put x - 1 = 0 
⇒ x = 1
Let F(x) = x4 + x3 - 2x2 + x + 1
⇒ F(1) = 14 + 13 - 2 × 12 + 1 + 1
⇒ F(1) = 1 + 1 - 2 + 1 + 1
⇒ F(1) = 4 - 2 = 2
∴Subtracting 2 from  x4 + x3 - 2x2 + x + 1 makes it divisible by x - 1.

Find the product of the polynomials (x - 2) and (x + 3).
  • a)
    x2 + x - 6
  • b)
    x2 - x - 6
  • c)
    x2+ 5x - 6
  • d)
    x2 - 5x + 6
Correct answer is option 'A'. Can you explain this answer?

To find the product of the polynomials, multiply each term in the first polynomial by each term in the second polynomial and then combine like terms:
(x - 2)(x + 3) = x(x) + x(3) - 2(x) - 2(3)
= x2 + 3x - 2x - 6
= x2 + x - 6.

What is the degree of the polynomial 4x3 - 2x2 + 5x - 3?
  • a)
    1
  • b)
    2
  • c)
    3
  • d)
    4
Correct answer is option 'C'. Can you explain this answer?

The degree of a polynomial is the highest power of the variable in the polynomial. In this case, the highest power is 3 (4x3), so the degree of the polynomial is 3.

Find the remainder when p(x) = 2x5 + 4x4 + 7x3 - x2 + 3x + 12 is divided by (x + 2).
  • a)
    -52
  • b)
    48
  • c)
    70
  • d)
    -54
Correct answer is option 'D'. Can you explain this answer?

We have, x + 2 = x - (-2)
So, by remainder theorem, when p(x) is divided by (x + 2) = (x - (-2)) the remainder is equal to p(-2).
Now, p(x) = 2x5 + 4x4 + 7x3 - x2 + 3x + 12
⇒ p(-2) = 2(-2)5 + 4(-2)4 + 7(-2)3 - (-2)2 + 3(-2) + 12
⇒ p(-2) = -2(32) + 4(16) - 7(8) - (4) - 6 + 12
⇒ p(-2) = -64 + 64 - 56 - 4 - 6 + 12
⇒ p(-2) =  -66 + 12
⇒ p(-2) = -54
Hence, required remainder = -54.

Which of the following expressions is a quadratic polynomial?
  • a)
    3x2 + 2x + 1
  • b)
    √x + 1
  • c)
    4x3 - 5x2 + 2x + 3
  • d)
    |x|
Correct answer is option 'A'. Can you explain this answer?

A quadratic polynomial is a polynomial of degree 2. It has the general form ax2 + bx + c, where a, b, and c are constants. Among the given options, only option A, 3x2 + 2x + 1, is a quadratic polynomial since it is of degree 2 and has the required form.

If 5x3 + 5x2 – 6x + 9 is divided by (x + 3), then the remainder is
  • a)
    135
  • b)
    -135
  • c)
    -63
  • d)
    63
Correct answer is option 'C'. Can you explain this answer?

Let p(x) = 5x3 + 5x2 – 6x + 9 
Since, (x + 3) divide p(x), then, remainder will be p(-3).
⇒ p(-3) = 5 × (-3)3 + 5 × (-3)2 – 6 × (-3) + 9
⇒ p(-3) = -63

The polynomial P(x) = x3 - 3x2 + 3x - 1 has a root at x =
  • a)
    x
    2
    - 2x + 1
  • b)
    x2 - 2x + 2
  • c)
    x2 - 4x + 3
  • d)
    x
    2
    - 4x + 4
Correct answer is option 'B'. Can you explain this answer?

Since P(x) has a root at x = 1, it must be divisible by (x - 1).
Using either synthetic or long division, we find
P(x) = (x - 1)(x2 - 2x + 2).

Which of the following is the remainder when the polynomial 2x3 - 3x2 + 4x - 5 is divided by x - 2?
  • a)
    -3
  • b)
    3
  • c)
    5
  • d)
    -5
Correct answer is option 'B'. Can you explain this answer?

Using synthetic division or the remainder theorem, we find the remainder when the polynomial is divided by
x - 2 is P(2) = 2(2)3 - 3(2)2 + 4(2) - 5
= 16 - 12 + 8 - 5
= 3.

Find the degree of the polynomial 2x5 + 2x3y3 + 4y4 + 5.
  • a)
    3
  • b)
    5
  • c)
    6
  • d)
    9
Correct answer is option 'C'. Can you explain this answer?

Degree of the polynomial in 2x5 = 5
Degree of the polynomial in 2x3y3 = 6
Degree of the polynomial in 4y4 = 4
Degree of the polynomial in 5 = 0
Hence, the highest degree is 6
∴ Degree of polynomial = 6

If a = 3 + 2√2, then find the value of (a6 – a4 – a2 + 1)/a3.
  • a)
    198
  • b)
    204
  • c)
    192
  • d)
    210
Correct answer is option 'C'. Can you explain this answer?

a = 3 + 2√2
1/a = 1/(3 + 2√2)
⇒ 1/a = (3 – 2√2)/{(3 + 2√2) × (3 – 2√2)}
⇒ 1/a = (3 – 2√2)/{32 – (2√2)2}
⇒ 1/a = (3 – 2√2)/(9 – 8)
⇒ 1/a = (3 – 2√2)
Now,
a + 1/a = 3 + 2√2 + 3 – 2√2
⇒ a + 1/a = 6
(a6 – a4 – a2 + 1)/a3
⇒ a3 – a – 1/a + 1/a3
⇒ (a3 + 1/a3) – (a + 1/a)
⇒ {(a + 1/a)3 – 3(a + 1/a)} – (a + 1/a)
⇒ (63 – 3 × 6) – 6
⇒ 216 – 18 – 6
⇒ 192
∴ The required value of (a6 – a4 – a2 + 1)/a3 is 192

If a polynomial has exactly 3 distinct roots, what is the minimum possible degree of the polynomial?
  • a)
    1
  • b)
    2
  • c)
    3
  • d)
    4
Correct answer is option 'C'. Can you explain this answer?

A polynomial can have at most as many distinct roots as its degree. To have exactly 3 distinct roots, the polynomial must have a minimum degree of 3.

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