Question

combine {sqrt -8} + {sqrt -32}

Answer 1

The answer in my book is \[6i - 2i \sqrt{10}\] I dont know how they got that answer.

Answer 2

You can't take the square root of a negative number

Answer 3

@ksaimouli is incorrect

Answer 4

thats why you multiply it by i which is equal to -1

Answer 5

@ksaimouli That's totally wrong. sqrt(a)+sqrt(b) is NOT sqrt(a+b).
@ilikephysics2 Yes, You can. That's what imaginary numbers are there for.
@karinewoods17 Notice that \[ \Large {\sqrt {8} = 2\sqrt{2}} \]and \[ \Large {\sqrt {32} = 4\sqrt{2}}, \]so \[ \Large {\sqrt {-8} = 2i\sqrt{2}} \]and \[ \Large {\sqrt {-32} = 4i\sqrt{2}} \]Do you see how that works? Now, just add to get 6isqrt(2).

Answer 6

wouldnt it be \[6i \sqrt{2}\] ??

Answer 7

\[\sqrt{-8}+\sqrt{-32}=\sqrt{-8}+\sqrt{-8\times4}= \sqrt{-8} + 2\sqrt{-8}\]

Answer 8

\[3\sqrt{-8}=3i \sqrt{8}=3i \sqrt{2\times4}=6i \sqrt{2}\]

Answer 9

Yes you are correct

Answer 10

Yep. That's exactly what I said, except I explained everything. =P

Answer 11

but... the answer in my book says the answer is \[6i - 2i \sqrt{10}\] How did they get that?

Answer 12

Im sorry:/ Im making coffee and waiting for you:)

Answer 13

im not! sorry!

Answer 14

I was making breakfast for my boyfriend.

Answer 15

umm. \[\sqrt{-32}\] breaks into \[\sqrt{-32} = \sqrt{4} * \sqrt{-8}\] which simplifies to \[4i \sqrt{2}\] ?

Answer 16

And yes I try:)

Answer 17

now what. lol

Answer 18

@nincompoop please do not ignore me;)