Question

Identify the number as​ real, complex, pure​ imaginary, or nonreal complex.​ (More than one of these descriptions may​ apply.) negative 1
a)non real complex
B)real
C) pure imaginary
D)complex

Answer 1

Since the number sets follow this pattern of inclusions:

$\mathbb{N} \subset \mathbb{Z} \subset \mathbb{Q} \subset \mathbb{R} \subset \mathbb{C}$

and $-1 \in \mathbb{Z}$, we can deduce that -1 is also a real number and a complex number (since if an element belongs to a set, it also belongs to all the supersets of its set).

So, the correct options are B and D.