Question

What is the absolute value of (3+4i) (3-4i)

Answer 1

First simplify. Use (a + b)(a - b) = a² - b²:

`(3+4i)(3-4i)=3^2-(4i)^2=9-4^2i^2=9-16(-1)=9+16=25`

Absolute value:

`|(3+4i)(3-4i)|=|25|=25`