Answer: 2.
- A 0
- B 1
- C 2
- D 3
Correct answer: C. 2
Explanation: Let t = 2<sup>x</sup> (t>0). 4t² - 10t + 4 = 0. 2t² - 5t + 2 = 0. (2t-1)(t-2) = 0. t = 1/2 or t = 2. x = -1 or x = 1. Two real solutions.
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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