Q. If the quadratic equation x^2 + 2x + 1 = 0 is solved, what is the nature of the roots? (2022)
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A.
Real and distinct
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B.
Real and equal
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C.
Complex
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D.
None of the above
Solution
The discriminant is 0, indicating that the roots are real and equal.
Correct Answer: B — Real and equal
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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)
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)
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 quadratic equation x^2 - 8x + 15 = 0 is solved, what are the roots? (2022)
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A.
3 and 5
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B.
2 and 6
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C.
1 and 7
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D.
4 and 4
Solution
Factoring gives (x - 3)(x - 5) = 0, hence the roots are 3 and 5.
Correct Answer: A — 3 and 5
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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?
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)
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)
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?
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)
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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Q. If the roots of the equation x^2 + 5x + c = 0 are 2 and 3, what is the value of c? (2022)
Solution
Using the product of the roots, c = 2 * 3 = 6.
Correct Answer: A — 6
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Q. If the roots of the equation x^2 + 6x + k = 0 are real and distinct, what must be the condition on k? (2023)
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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 leads to k < 9.
Correct Answer: A — k < 9
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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 roots of the quadratic equation ax^2 + bx + c = 0 are equal, which of the following must be true? (2019)
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A.
b^2 > 4ac
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B.
b^2 < 4ac
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C.
b^2 = 4ac
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D.
a + b + c = 0
Solution
For the roots to be equal, the discriminant must be zero, which means b^2 = 4ac.
Correct Answer: C — b^2 = 4ac
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Q. If the roots of the quadratic equation x^2 + 2x + k = 0 are equal, what is the value of k? (2022)
Solution
For the roots to be equal, the discriminant must be zero. Thus, 2^2 - 4*1*k = 0 leads to k = 1.
Correct Answer: D — -1
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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)
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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 = -5, what is the value of |x|?
Solution
The absolute value |x| of -5 is 5.
Correct Answer: C — 5
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Q. If x = 3 and y = 4, what is the value of x² + y²?
Solution
x² + y² = 3² + 4² = 9 + 16 = 25.
Correct Answer: A — 25
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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 x = 4, what is the value of 3x - 2? (2019)
Solution
3x - 2 = 3(4) - 2 = 12 - 2 = 10.
Correct Answer: B — 12
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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 = 2 + 2i, what is the argument of z? (2023)
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A.
π/4
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B.
π/2
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C.
3π/4
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D.
0
Solution
The argument of z is given by tan^(-1)(2/2) = tan^(-1)(1) = π/4.
Correct Answer: A — π/4
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Q. If z = 2(cos(π/3) + i sin(π/3)), what is z in rectangular form? (2022)
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A.
1 + √3i
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B.
2 + √3i
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C.
1 + 2i
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D.
2 + 2i
Solution
Using Euler's formula, z = 2(cos(π/3) + i sin(π/3)) = 2(1/2 + i√3/2) = 1 + √3i.
Correct Answer: A — 1 + √3i
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