Question

What is the value of the product (3-2i) (3+2i)

Answer 1

`\large\boxed{(3-2i)(3+2i)=13}`

Explanation:

`(3-2i)(3+2i)\qquad\text{use}\ (a-b)(a+b)=a^2-b^2\\\\=3^2-(2i)^2=9-4i^2\qquad i=√(-1)\to i^2=-1\\\\=9-4(-1)=9+4=13`