Q. If the roots of the equation x^2 - 4x + k = 0 are real and distinct, what is the condition for k? (2023)
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A.
k > 4
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B.
k < 4
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C.
k = 4
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D.
k ≤ 4
Solution
The discriminant must be greater than zero for real and distinct roots: (-4)^2 - 4*1*k > 0, which simplifies to 16 - 4k > 0, or k < 4.
Correct Answer: A — k > 4
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Q. If the roots of the equation x^2 - 6x + k = 0 are real and distinct, what is the range of k? (2020)
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A.
k < 9
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B.
k > 9
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C.
k = 9
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D.
k ≤ 9
Solution
For real and distinct roots, the discriminant must be greater than zero: (-6)^2 - 4*1*k > 0, leading to k < 9.
Correct Answer: A — k < 9
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Q. If the sum of the roots of the equation x^2 + px + q = 0 is 5 and the product is 6, what are the values of p and q? (2023)
-
A.
-5, 6
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B.
-5, -6
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C.
5, 6
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D.
5, -6
Solution
From Vieta's formulas, p = -sum of roots = -5 and q = product of roots = 6.
Correct Answer: A — -5, 6
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Q. If the sum of two numbers is 12 and their product is 32, what are the numbers?
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A.
4 and 8
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B.
6 and 6
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C.
2 and 10
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D.
3 and 9
Solution
The numbers are 4 and 8, as 4 + 8 = 12 and 4 × 8 = 32.
Correct Answer: A — 4 and 8
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Q. If x + y = 10 and xy = 21, what is the value of x^2 + y^2? (2021)
Solution
We know that x^2 + y^2 = (x + y)^2 - 2xy. Substituting the values, we get (10)^2 - 2(21) = 100 - 42 = 58.
Correct Answer: A — 49
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Q. If x = -3, what is the value of |x| + x?
Solution
|-3| = 3, so |x| + x = 3 - 3 = 0.
Correct Answer: B — -3
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Q. If x = 4, what is the value of 2x - 3? (2022)
Solution
2x - 3 = 2(4) - 3 = 8 - 3 = 5.
Correct Answer: C — 7
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Q. If z = 1 + i, find |z|².
Solution
|z|² = (1)² + (1)² = 1 + 1 = 2.
Correct Answer: B — 2
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Q. If z = 1 + i, what is the value of z^3? (2023)
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A.
-2 + 2i
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B.
2i
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C.
0
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D.
2 + 2i
Solution
z^3 = (1 + i)^3 = 1 + 3i + 3i^2 + i^3 = 1 + 3i - 3 - i = -2 + 2i.
Correct Answer: A — -2 + 2i
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Q. If z = 1 + i√3, find the conjugate of z.
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A.
1 - i√3
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B.
1 + i√3
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C.
1 + √3i
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D.
1 - √3i
Solution
The conjugate of a complex number z = a + bi is given by z* = a - bi. Thus, the conjugate of z = 1 + i√3 is 1 - i√3.
Correct Answer: A — 1 - i√3
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Q. If z = 1 + i√3, what is the value of z^2? (2023)
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A.
-2 + 2i√3
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B.
4
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C.
1 - 2i√3
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D.
1 + 2i√3
Solution
z^2 = (1 + i√3)^2 = 1^2 + 2(1)(i√3) + (i√3)^2 = 1 + 2i√3 - 3 = -2 + 2i√3.
Correct Answer: A — -2 + 2i√3
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Q. If z = 2 + 2i, find z².
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A.
0
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B.
8i
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C.
8
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D.
4 + 8i
Solution
z² = (2 + 2i)² = 4 + 8i - 4 = 8i.
Correct Answer: C — 8
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Q. If z = 3 + 4i, what is the modulus of z? (2021)
Solution
The modulus of z is given by |z| = √(3^2 + 4^2) = √(9 + 16) = √25 = 5.
Correct Answer: A — 5
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Q. If z1 = 2 + 2i and z2 = 2 - 2i, what is the value of z1 * z2? (2019)
Solution
z1 * z2 = (2 + 2i)(2 - 2i) = 4 - 4i^2 = 4 + 4 = 8.
Correct Answer: A — 8
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Q. In the expansion of (2x - 3)^4, what is the coefficient of x^3? (2023)
-
A.
-108
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B.
-72
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C.
72
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D.
108
Solution
The coefficient of x^3 in (2x - 3)^4 is given by 4C1 * (2)^3 * (-3)^1 = 4 * 8 * (-3) = -96. The coefficient is -108.
Correct Answer: A — -108
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Q. In the expansion of (3x - 4)^7, what is the coefficient of x^5? (1920)
-
A.
1260
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B.
1440
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C.
1680
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D.
1920
Solution
Using the binomial theorem, the coefficient of x^5 in (3x - 4)^7 is given by 7C5 * (3)^5 * (-4)^2 = 21 * 243 * 16 = 21 * 3888 = 81588.
Correct Answer: A — 1260
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Q. In the expansion of (x + 3)^6, what is the coefficient of x^4?
-
A.
540
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B.
720
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C.
810
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D.
900
Solution
Using the binomial theorem, the coefficient of x^4 in (x + 3)^6 is given by 6C4 * (3)^2 = 15 * 9 = 135.
Correct Answer: B — 720
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Q. The equation x^2 - 7x + 10 = 0 has roots that are:
-
A.
1 and 10
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B.
2 and 5
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C.
3 and 4
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D.
5 and 2
Solution
Factoring the equation gives (x - 2)(x - 5) = 0, so the roots are 2 and 5.
Correct Answer: C — 3 and 4
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Q. The quadratic equation 2x^2 - 4x + k = 0 has no real roots. What is the condition for k? (2022)
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A.
k < 0
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B.
k > 0
-
C.
k > 8
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D.
k < 8
Solution
The discriminant must be less than zero: (-4)^2 - 4*2*k < 0 leads to k > 8.
Correct Answer: C — k > 8
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Q. The quadratic equation x^2 + 6x + 9 = 0 can be expressed in which of the following forms? (2020)
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A.
(x + 3)^2
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B.
(x - 3)^2
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C.
(x + 6)^2
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D.
(x - 6)^2
Solution
This is a perfect square trinomial: (x + 3)(x + 3) = 0.
Correct Answer: A — (x + 3)^2
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Q. The quadratic equation x^2 + 6x + k = 0 has roots that are both negative. What is the condition for k? (2020)
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A.
k > 9
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B.
k < 9
-
C.
k = 9
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D.
k = 0
Solution
For both roots to be negative, k must be greater than the square of half the coefficient of x, hence k > 9.
Correct Answer: A — k > 9
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Q. The roots of the equation x^2 + 3x + k = 0 are -1 and -2. What is the value of k? (2021)
Solution
The sum of the roots is -1 + (-2) = -3, and the product is (-1)(-2) = 2. Thus, k = 2.
Correct Answer: A — 2
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Q. The roots of the quadratic equation x^2 - 4x + k = 0 are 2 and 2. What is the value of k? (2022)
Solution
If the roots are both 2, then k = 2^2 - 4*2 = 4 - 8 = -4. Thus, k = 4.
Correct Answer: C — 4
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Q. The sum of the roots of the equation x^2 - 7x + k = 0 is 7. What is the value of k if the product of the roots is 10? (2023)
Solution
Using Vieta's formulas, the sum of the roots is 7 and the product is k = 10.
Correct Answer: A — 10
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Q. The sum of the roots of the quadratic equation 3x^2 + 12x + 12 = 0 is equal to what? (2022)
Solution
Using Vieta's formulas, the sum of the roots is -b/a = -12/3 = -4.
Correct Answer: A — -4
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Q. What is the absolute value of -7? (2023)
Solution
The absolute value of -7 is 7.
Correct Answer: C — 7
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Q. What is the coefficient of x^2 in the expansion of (2x + 5)^4?
-
A.
60
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B.
80
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C.
100
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D.
120
Solution
Using the binomial theorem, the coefficient of x^2 in (2x + 5)^4 is given by 4C2 * (2)^2 * (5)^2 = 6 * 4 * 25 = 600.
Correct Answer: A — 60
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Q. What is the coefficient of x^2 in the expansion of (2x - 5)^5? (2019)
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A.
-300
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B.
-600
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C.
600
-
D.
300
Solution
The coefficient of x^2 in (2x - 5)^5 is given by 5C2 * (2)^2 * (-5)^3 = 10 * 4 * (-125) = -5000.
Correct Answer: B — -600
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Q. What is the coefficient of x^3 in the expansion of (3x + 2)^5? (2023)
-
A.
90
-
B.
180
-
C.
270
-
D.
360
Solution
The coefficient of x^3 in (3x + 2)^5 is given by 5C3 * (3)^3 * (2)^2 = 10 * 27 * 4 = 1080.
Correct Answer: B — 180
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Q. What is the product of the roots of the equation 2x^2 - 8x + 6 = 0?
Solution
The product of the roots of the equation ax^2 + bx + c = 0 is given by c/a. Here, c = 6 and a = 2, so the product is 6/2 = 3.
Correct Answer: A — 3
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