Answer: x² - 8x + 15 = 0.
- A x² - 8x + 15 = 0
- B x² + 8x + 15 = 0
- C x² - 15x + 8 = 0
- D x² + 15 = 0
Correct answer: A. x² - 8x + 15 = 0
Explanation: Sum = 8, product = 15. Equation: x² - (sum)x + product = 0, so x² - 8x + 15 = 0.
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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