Answer: x² - x + 1.
- A x² - x + 1
- B x² - 4
- C x² - 2x
- D x² - 3x - 4
Correct answer: A. x² - x + 1
Explanation: D = 1 - 4 = -3 < 0 and a > 0 for x² - x + 1. Negative D + positive a means always positive.
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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