Question

simplify and write in a+bi form (5-4i)^2
is 25-16i correct?

Answer 1

not actually
did you use this ?
\((x-y)^2 = x^2-2xy+y^2\)
?

Answer 2

nope. I'll try it (:

Answer 3

is 5 x and 4y?

Answer 4

you mean x=5
and y= 4i
then yes

Answer 5

\(\Large 5^2 - 2\times 5\times 4i +(4i)^2 =...\)
try to simplify :)

Answer 6

476i?

Answer 7

lol how? :P

ok, 5^2 = 25
\(\large (4i)^2 = 4^2i^2 = 16i^2=...?\)

you know the value of \(\large i^2 \)
??

Answer 8

115(16i^2)?

Answer 9

you know what 'i' is ?

Answer 10

imaginary

Answer 11

did you know
\(\huge i=\sqrt{-1}\)

?

Answer 12

now you know,
so can you tell me what will be
\(\large i^2 = (\sqrt{-1})^2=... ?\)

Answer 13

oh (: 1

Answer 14

actually
\(\large i^2 = (\sqrt{-1})^2=-1\)
:)

Answer 15

5^2-2x5x4i+16i^2= 15x4+-16= 44?

Answer 16

\(\Large 5^2 - 2\times 5\times 4i +(4i)^2 =25 -40i +16i^2\)
but \(i^2 = -1\)

Answer 17

\(\Large 5^2 - 2\times 5\times 4i +(4i)^2 =25 -40i +16i^2 \\ \large = 25 -40i+16(-1)\)

did u get this ?
try to simplify further :)

Answer 18

9-40i?

Answer 19

now that, my dear, is absolutely correct! :)

Answer 20

Thank you beautiful soul :D

Answer 21

lol, welcome beautiful.....everything :P ^_^