Question

Your friend multiplied complex numbers and expressions as shown. Find the error in your friends work. Then factor the expression correctly. Show work please.
(4-7i)(4+7i)=16+28i-28i+49i^2
=16-49
=-33

Answer 1

Answer:

  = 16+49 = 65

Step-by-step explanation:

The error is at the end of the first line. (-7i)(7i) = -49i² ≠ +49i².

The correct work is ...

  (4-7i)(4+7i)=16+28i-28i-49i^2

  = 16+49

  = 65