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📐 Mathematics  ·  Complex Numbers and Quadratic Equations  ·  JEE

x = 3 is a root of x² - 5x + 6 = 0. Find the other root.

Answer: 2.

  • A 1
  • B 2
  • C 3
  • D 4

Correct answer: B. 2

Explanation: Sum of roots = 5, so other root = 5 - 3 = 2. Or product = 6, so other = 6/3 = 2.

Argand Plane: z = a + ibReImz = a+iba (real part)b (imaginary part)θ = arg(z)|z| = length of the vector OZ = √(a²+b²); θ = angle OZ makes with the positive real axis

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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