Question

Find the product of each complex number and its conjugate.

20. 5
23. 9i

Answer 1

\[9i\] as in imaginary number

Answer 2

\[\Large\rm 5=5+0i\]
\[\Large\rm (5+0i)(5-0i)=?\]

Answer 3

So if a term is missing, either real number or imaginary, it is an unwritten zero?

Answer 4

yes! :)

Answer 5

Certainly makes your multiplication easier huh? ^^

Answer 6

Careful with 23 though,\[\Large\rm (0+9i)(0-9i)\neq 9i\cdot 9i\]

Answer 7

I've got it from here!
20. 5 = 25
23. 9i = 9

Answer 8

9^2 for 23, ya? :)

Answer 9

\[-9i^2 = -9 * -1 = 9 \] right?

Answer 10

\[\Large\rm (0+9i)(0-9i)= 9i\cdot(-9i)=-(9i)^2=-9^2i^2\]

Answer 11

Oh woops, just a careless mistake I made. Thanks!

Answer 12

np c: