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February 1, 2015

February 1, 2015

Posted by **Jack** on Wednesday, October 5, 2011 at 6:59am.

it says

25 = 16 - 9 i^2 = (4 ± 3i)

But My Teacher Says

25 = 25 - 0 i^2 = (5 ± 0i)

I Think My Teacher Is Wrong , The Result Is 25 But There Will Not Be Complex Number Because ( 0i = 0)

So Is My Teacher Wrong Or Not ?

- Math -
**Reiny**, Wednesday, October 5, 2011 at 8:31amboth end statements are incorrect

(4 ± 3i) means (4+3i) OR (4-3i)

it has nothing to do with the multiplication of

(4+3i)(4-3i)

which would be

16 - 9i^2

= 16 - (-9)

= 25

your teacher should have said, (probably did)

(5 + 0i)(5-0i)

= 25 - 0i^2

= 25

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