Algebra
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 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 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 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, 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 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 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. How many ways can 2 boys and 3 girls be selected from 6 boys and 4 girls? (2023)
A.
60
B.
80
C.
100
D.
120
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Solution
The number of ways is 6C2 * 4C3 = 15 * 4 = 60.
Correct Answer: A — 60
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Q. How many ways can 4 students be selected from a class of 10? (2020)
A.
210
B.
120
C.
240
D.
300
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Solution
The number of ways to choose 4 students from 10 is given by 10C4 = 210.
Correct Answer: A — 210
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Q. If a + b = 12 and a^2 + b^2 = 70, what is the value of ab? (2019)
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Solution
Using the identity a^2 + b^2 = (a + b)^2 - 2ab, we have 70 = 12^2 - 2ab. Thus, 70 = 144 - 2ab, leading to ab = 37.
Correct Answer: A — 20
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Q. If a = 2 and b = 3, what is the value of a^2 + b^2?
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Solution
a^2 = 4 and b^2 = 9, so 4 + 9 = 13.
Correct Answer: C — 13
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Q. If log_2(x) + log_2(4) = 6, what is the value of x?
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Solution
log_2(x) + 2 = 6 implies log_2(x) = 4, so x = 2^4 = 16.
Correct Answer: C — 32
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Q. If log_3(x) = 4, what is the value of x?
A.
27
B.
81
C.
243
D.
729
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Solution
log_3(x) = 4 implies x = 3^4 = 81.
Correct Answer: C — 243
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Q. If log_4(256) = x, what is the value of x? (2022)
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Solution
log_4(256) = log_4(4^4) = 4.
Correct Answer: D — 8
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Q. If log_a(16) = 4, what is the value of a? (2021)
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Solution
log_a(16) = 4 implies a^4 = 16. Since 16 = 2^4, we have a^4 = 2^4, thus a = 2.
Correct Answer: A — 2
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Q. If log_b(25) = 2, what is the value of b?
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Solution
log_b(25) = 2 implies b^2 = 25. Therefore, b = 5.
Correct Answer: A — 5
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Q. If log_x(64) = 6, what is the value of x? (2023)
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Solution
log_x(64) = 6 implies x^6 = 64. Since 64 = 2^6, we have x = 2.
Correct Answer: C — 8
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Q. If one root of the quadratic equation x^2 + px + q = 0 is 3, and the other root is -1, what is the value of p? (2021)
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Solution
The sum of the roots is 3 + (-1) = 2, hence p = -2.
Correct Answer: A — 2
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Q. If the quadratic equation ax^2 + bx + c = 0 has roots p and q, what is the value of p + q? (2020)
A.
-b/a
B.
b/a
C.
c/a
D.
-c/a
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Solution
By Vieta's formulas, the sum of the roots p + q = -b/a.
Correct Answer: A — -b/a
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Q. If the quadratic equation x^2 + 2x + 1 = 0 is solved, what are the roots? (2022)
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Solution
The equation can be factored as (x + 1)(x + 1) = 0, giving the root -1 with multiplicity 2.
Correct Answer: A — -1
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Q. If the quadratic equation x^2 + 2x + k = 0 has one root equal to -1, what is the value of k? (2022)
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Solution
Substituting x = -1 into the equation gives (-1)^2 + 2(-1) + k = 0, leading to 1 - 2 + k = 0, thus k = 1.
Correct Answer: B — 1
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Q. If the quadratic equation x^2 + px + q = 0 has roots 3 and 4, what is the value of p + q? (2023)
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Solution
Using Vieta's formulas, p = -(3 + 4) = -7 and q = 3 * 4 = 12. Therefore, p + q = -7 + 12 = 5.
Correct Answer: B — 12
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Q. If the roots of the equation x^2 + 2x + 1 = 0 are equal, what is the value of the discriminant?
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Solution
The discriminant is given by b^2 - 4ac. Here, b = 2, a = 1, c = 1, so the discriminant is 2^2 - 4*1*1 = 0.
Correct Answer: A — 0
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Q. If the roots of the equation x^2 + 2x + k = 0 are -1 and -3, what is the value of k? (2022)
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Solution
The sum of the roots is -1 + -3 = -4, and the product is (-1)(-3) = 3. Thus, k = 3.
Correct Answer: C — 4
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Q. If the roots of the equation x^2 + 3x + k = 0 are -1 and -2, what is the value of k? (2023)
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Solution
Using Vieta's formulas, k = (-1)(-2) = 2.
Correct Answer: A — 2
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Q. If the roots of the equation x^2 + 4x + k = 0 are equal, what is the value of k?
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Solution
For the roots to be equal, the discriminant must be zero. Thus, 4^2 - 4*1*k = 0 leads to k = 4.
Correct Answer: B — 8
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Q. If the roots of the equation x^2 + 5x + 6 = 0 are a and b, what is the value of ab? (2023)
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Solution
The product of the roots ab is given by c/a. Here, c = 6 and a = 1, so ab = 6.
Correct Answer: A — 6
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