Question

How does (x-4+3i)(x-4-3i) = x(^2)-8x+25 ?

Answer 1

have you tried to multiply it out?

Answer 2

Nope, don't know how, that's why I'm here.

Answer 3

pretty rusty admittedly

Answer 4

x -4 +3i
x -4 -3i
---------
x^2 -4x +3xi
-4x +16 -12i
-3xi +12i -9i^2
---------------------------
x^2 -8x +16 -9(-1)

x^2 -8x + 25

Answer 5

you might be used to multiplying from right to left tho; in numbers ...

i find it easier to start left to right on these things tho

Answer 6

then its just a matter of aligning like terms as you go

Answer 7

x -4 +3i
x -4 -3i
---------------------------
-3xi +12i -9i^2
-4x +16 -12i
x^2 -4x +3xi
---------------------------
x^2 -8x +16 -9(-1)

x^2 -8x + 25

Answer 8

dont be shy now, if you got questions about the method, go ahead and ask :)

Answer 9

I got the alignment thing I was already realigning it my way copying it but so... just to clarify... pardon me, I like math, I do... but uh... that's even more unfortunate because i^2 is always equal to -1?

Answer 10

yes, "i" has a special meaning in mathematics; it is the symbol used to express the value for the sqrt(-1)

i^2 = sqrt(-1)*sqrt(-1) = -1

Answer 11

it is not a "real number"; it is an "imaginary" number; which is another sad side effect of how people used to name stuff

Answer 12

Oh pellet okay I know it's "imaginary" but I thought that just meant sqrt of any negative, that's where I was confused. Thanks.

Answer 13

youre welcome, and i see the censor is working lol

Answer 14

hahahaha

Answer 15

pellet