Q. Determine the coefficient of x^5 in the expansion of (3x - 4)^7.
A.
252
B.
336
C.
672
D.
840
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Solution
The coefficient of x^5 in (3x - 4)^7 is C(7, 5) * (3)^5 * (-4)^2 = 21 * 243 * 16 = 68016.
Correct Answer: A — 252
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Q. Find the coefficient of x^2 in the expansion of (2x - 3)^4.
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Solution
Using the binomial theorem, the coefficient of x^2 in (2x - 3)^4 is given by 4C2 * (2)^2 * (-3)^2 = 6 * 4 * 9 = 216.
Correct Answer: C — 54
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Q. Find the coefficient of x^2 in the expansion of (3x - 2)^5.
A.
-60
B.
-90
C.
90
D.
60
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Solution
The coefficient of x^2 in (3x - 2)^5 is given by 5C2 * (3x)^2 * (-2)^3 = 10 * 9 * (-8) = -720.
Correct Answer: B — -90
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Q. Find the coefficient of x^4 in the expansion of (x + 1)^8.
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Solution
The coefficient of x^4 is C(8, 4) = 70.
Correct Answer: A — 70
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Q. Find the value of (1 + i)².
A.
2i
B.
2
C.
0
D.
1 + 2i
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Solution
(1 + i)² = 1² + 2(1)(i) + i² = 1 + 2i - 1 = 2i.
Correct Answer: B — 2
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Q. Find the value of k if the coefficient of x^2 in the expansion of (x + k)^4 is 6.
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Solution
The coefficient of x^2 in (x + k)^4 is C(4, 2) * k^2 = 6. Thus, 6k^2 = 6, giving k^2 = 1, so k = 1 or -1.
Correct Answer: B — 2
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Q. Find the value of k in the expansion of (x + 2)^6 such that the term containing x^4 is 240.
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Solution
The term containing x^4 is C(6,4) * (2)^2 * x^4 = 15 * 4 * x^4 = 60x^4. Setting 60 = 240 gives k = 4.
Correct Answer: A — 4
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Q. Find the value of the binomial coefficient C(7, 4).
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Solution
C(7, 4) = 7! / (4! * (7-4)!) = 7! / (4! * 3!) = (7*6*5)/(3*2*1) = 35.
Correct Answer: B — 35
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Q. Find the value of the coefficient of x^4 in the expansion of (x - 2)^6.
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Solution
Using the binomial theorem, the coefficient of x^4 in (a + b)^n is given by nCk * a^(n-k) * b^k. Here, n=6, a=x, b=-2, and k=2. Thus, the coefficient is 6C2 * (1)^4 * (-2)^2 = 15 * 4 = 60.
Correct Answer: C — 30
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Q. For the cubic equation x^3 - 3x^2 + 3x - 1 = 0, which of the following is a root?
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Solution
By substituting x = 1 into the equation, we find that it satisfies the equation, hence 1 is a root.
Correct Answer: C — 1
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Q. For the equation x^2 + 6x + k = 0 to have no real roots, what must be the condition on k?
A.
k < 0
B.
k > 0
C.
k = 0
D.
k ≤ 0
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Solution
The condition for no real roots is that the discriminant must be less than zero: 6^2 - 4*1*k < 0 => 36 < 4k => k > 9.
Correct Answer: D — k ≤ 0
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Q. For the equation x^3 - 3x^2 + 3x - 1 = 0, how many real roots does it have?
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Solution
The equation can be factored as (x-1)^3 = 0, which has one real root (x = 1) with multiplicity 3.
Correct Answer: A — 1
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Q. For the equation x^3 - 6x^2 + 11x - 6 = 0, what is the product of the roots? (2019)
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Solution
The product of the roots of the cubic equation ax^3 + bx^2 + cx + d = 0 is given by -d/a. Here, d = -6 and a = 1, so the product is -(-6)/1 = 6.
Correct Answer: A — 6
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Q. For the equation x^3 - 6x^2 + 11x - 6 = 0, which of the following is a root?
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Solution
By substituting x = 2 into the equation, we find that 2 is a root since 2^3 - 6(2^2) + 11(2) - 6 = 0.
Correct Answer: B — 2
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Q. For the polynomial x^3 - 3x^2 + 3x - 1, what is the nature of its roots? (2020)
A.
All real and distinct
B.
All real and equal
C.
One real and two complex
D.
All complex
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Solution
The polynomial can be factored as (x-1)^3, indicating that it has one real root with multiplicity 3, hence all roots are real and equal.
Correct Answer: B — All real and equal
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Q. For the polynomial x^3 - 3x^2 + 3x - 1, what is the value of the sum of the roots? (2019)
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Solution
The sum of the roots is given by -b/a = 3/1 = 3.
Correct Answer: B — 3
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Q. For the polynomial x^3 - 3x^2 + 3x - 1, which of the following is true about its roots?
A.
All roots are real
B.
All roots are complex
C.
One root is real
D.
Two roots are real
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Solution
The polynomial can be factored as (x - 1)^3, indicating that all roots are real and equal.
Correct Answer: A — All roots are real
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Q. For the quadratic equation 2x^2 + 4x + 2 = 0, what is the value of the discriminant? (2020)
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Solution
The discriminant D = b^2 - 4ac = 4^2 - 4(2)(2) = 16 - 16 = 0.
Correct Answer: A — 0
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Q. For the quadratic equation 2x^2 + 4x + k = 0 to have equal roots, what should be the value of k? (2020)
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Solution
For equal roots, the discriminant must be zero: b^2 - 4ac = 0. Here, 4^2 - 4(2)(k) = 0 leads to k = 4.
Correct Answer: A — -4
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Q. For the quadratic equation 2x^2 + 4x + k = 0 to have real roots, what must be the condition on k? (2019)
A.
k > 4
B.
k < 4
C.
k >= 4
D.
k <= 4
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Solution
The discriminant must be non-negative: 4^2 - 4*2*k >= 0, which simplifies to k <= 4.
Correct Answer: D — k <= 4
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Q. For the quadratic equation 2x^2 + 4x - 6 = 0, what is the value of the discriminant? (2020)
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Solution
The discriminant D = b^2 - 4ac = 4^2 - 4(2)(-6) = 16 + 48 = 64.
Correct Answer: A — 16
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Q. For the quadratic equation 2x^2 - 4x + k = 0 to have equal roots, what must be the value of k? (2019)
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Solution
For equal roots, the discriminant must be zero: (-4)^2 - 4*2*k = 0. Solving gives k = 4.
Correct Answer: C — 4
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Q. For the quadratic equation x^2 + 2px + p^2 - 4 = 0, what condition must p satisfy for the roots to be real? (2023)
A.
p > 2
B.
p < 2
C.
p = 2
D.
p >= 2
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Solution
The discriminant must be non-negative: (2p)^2 - 4(1)(p^2 - 4) >= 0 leads to p >= 2.
Correct Answer: D — p >= 2
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Q. For the quadratic equation x^2 + 6x + 9 = 0, what type of roots does it have? (2019)
A.
Real and distinct
B.
Real and equal
C.
Complex
D.
None of the above
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Solution
The discriminant D = 6^2 - 4*1*9 = 0, indicating real and equal roots.
Correct Answer: B — Real and equal
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Q. For the quadratic equation x^2 + 6x + k = 0 to have real roots, what must be the condition on k? (2020)
A.
k < 9
B.
k = 9
C.
k > 9
D.
k ≤ 9
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Solution
The discriminant must be non-negative: 6^2 - 4(1)(k) ≥ 0, which gives k ≤ 9.
Correct Answer: D — k ≤ 9
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Q. For the quadratic equation x^2 + px + q = 0, if the roots are -2 and -3, what is the value of p? (2020)
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Solution
The sum of the roots is -(-2) + -(-3) = 5, hence p = 5.
Correct Answer: A — 5
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Q. For the quadratic equation x^2 - 4x + 4 = 0, what type of roots does it have? (2019)
A.
Real and distinct
B.
Real and equal
C.
Complex
D.
None of the above
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Solution
The discriminant is 0, indicating that the roots are real and equal.
Correct Answer: B — Real and equal
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Q. For the quadratic equation x^2 - 6x + k = 0 to have one root equal to 3, what is the value of k? (2023)
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Solution
If one root is 3, then substituting x = 3 gives 3^2 - 6*3 + k = 0, leading to k = 9.
Correct Answer: C — 9
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Q. For which value of k does the equation x^2 + kx + 16 = 0 have equal roots? (2019)
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Solution
For equal roots, the discriminant must be zero: k^2 - 4*1*16 = 0. Solving gives k = -8.
Correct Answer: B — -4
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Q. From a group of 8 people, how many ways can a team of 3 be selected? (2022)
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Solution
The number of ways to choose 3 people from 8 is given by 8C3 = 56.
Correct Answer: A — 56
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