Question

Can someone show me how to do this problem step by step? (8+9i)(8-9i)

Answer 1

ok expand the brackets the same way u do when u have x\[(8+9i)(8-9i)\]\[64-72i+72i -9i^2\]right?

Answer 2

so the -72i +72i =0 so u cancel them

and do u know what i^2 =?

Answer 3

\[i=\sqrt{-1} \]\[i^2= -1\]

Answer 4

so it becomes
\[64-9(-1) = 64+9\]

Answer 5

=73

Answer 6

64+81=145

Answer 7

oops my bad\[64-72i+72i -81i^2 = 64-81(-1) = 64+81= 145\]

Answer 8

thank you

Answer 9

=)