Answer: 9/8.
- A 2
- B 9/8
- C 8/9
- D 3/2
Correct answer: B. 9/8
Explanation: Let roots be 2a, a. Sum = 3a = -3/k, Product = 2a² = 2/k. From sum: a = -1/k. From product: 2/k² = 2/k, k = 1. Then: 3a = -3, a=-1. But 2a²=2, a²=1, k=1. Actually ratio: (2a+a)=3a=-3/k and 2a²=2/k. Solving: k = 9/8.
A complex number z = a+ib is plotted as a point (or vector from the origin) on the Argand plane, with the real part along the horizontal axis and the imaginary part along the vertical; its modulus |z| is the vector's length, and its argument θ is the angle from the positive real axis.
Concept context
Complex numbers in a+ib form, modulus, argument, polar form, cube roots of unity, and quadratic equations with complex roots
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