Answer: x = ±2.
- A x = 2, just one of the two valid roots
- B x = -2, just the other valid root alone
- C x = ±2
- D x = ±4, doubling the actual correct values
Correct answer: C. x = ±2
Explanation: x² = 4, so x = ±√4 = ±2. Square roots always give two values (positive and negative).
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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