Question

Which of the following is a complex number? a. -7 b. 2+√3 c. 4+9i d. π

Answer 1

Hello,

Answer C
=============

Answer 2

Answer: C. 4+9i

Step-by-step explanation:

A combination of a real and an imaginary number is called complex number.

Since, - 7 is the negative integer and an integer is always the real number only therefore it can not be the complex number,

2+√3 is the irrational number which is only a real number therefore,  it can not be the complex number,

In  number 4+9i, 4 is the real number and 9i is the imaginary number, Therefore it is a complex number,

π is the irrational number and an irrational number is always a real number therefore it can be the complex number.

Thus, Option C is correct.