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📐 Mathematics  ·  Complex Numbers and Quadratic Equations  ·  JEE

The number of real roots of (x-1)(x+3) = 0 is:

Answer: 2.

  • A 0
  • B 1
  • C 2
  • D 4

Correct answer: C. 2

Explanation: Product = 0 gives x = 1 or x = -3. Two distinct real roots.

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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