Question

find the product for (5+3i)(5-3i)... I got 24-9a. Does anyone know if this is correct?

Answer 1

Should be 25-9i. You use foil if you've ever been taught that.

Answer 2

No i, my bad.

Answer 3

yeah, that's what I used.. and since the 9i was squared i added a -1. must have calculated it our wrong. Thanks

Answer 4

yeah, do the i's cancel out? So it would be 25-9?

Answer 5

And actually should be adding. Let's start over lol.

Answer 6

ha good call!

Answer 7

25-9i^2. That is what you should get, which can be simplified.

Answer 8

ok so I can add the 2 and the 25?

Answer 9

Ok. So i represents an imaginary number, it's what you get when you take the square root of a negative number. And the ^ is raised to a power. So we have 25-9i^2. So if \[i=\sqrt{-1}\] then \[i^2=-1\] So we get 25-9(-1)

Answer 10

someone help me

Answer 11

ok so would that be the answer? or can I simplify from there? Since there aren't any i's do I need to add those all to get one number?

Answer 12

Yes to more simplifying. 25-9(-1) is the same as 25+9=34

Answer 13

oh so the answer should be just 34?

Answer 14

Yep.

Answer 15

Thanksabunch

Answer 16

No problem. :)