Complex Number: Number of the form a + bi, where the real part is a and the imaginary part is bi; both a and b are real numbers and i is the square root of -1.

Complex number plane: A plane with perpendicular number lines, where the horizontal is the real part of a complex number and the vertical one is the imaginary part.

Conjugates: Binomials in the form a√(b) +c√(d) and  a√(b) +c√(d) for which a, b, c, and d are rational numbers.

i It is the imaginary unit. The one to indicate the imaginary part of a complex number. i is the square root of -1.

Imaginary Number: A number in the form of bi, where i² = -1 and thus i is the square root of -1.

Real number:  Any number rational or irrational, with exception of the imaginary numbers all numbers are real numbers.