Question

SI Negative Square root help please?

Answer 1

the first thing is write is as
\[ \sqrt{-1} \sqrt{320} \]
and use the short-hand i for the \(\sqrt{-1} \)
\[ i \sqrt{320} \]

Answer 2

now you simplify the square root of 320 which will be positive numbers inside or outside of the radical. in other words, the answer will have an i, and will be positive.

Answer 3

I've simplified 320 to the square roots of 160 and 2

Answer 4

I'm unsure of what to do after though

Answer 5

Wait! Perfect square.. square root of 64 and square root of 5 = 320.. and that would be 8i square root of 5

Answer 6

one strategy is break 320 into its *prime* factors
(which are numbers that cannot be broken down into smaller factors)
the first few primes are 2,3,5,7,11,13
divide by 2 to get
2*160
now divide 160 by 2
2*2*80
keep going
2*2*2*40
2*2*2*2*20
2*2*2*2*2*10
2*2*2*2*2*2*5

now "pull out pairs"


\[ \sqrt{(2 \cdot 2) \cdot(2 \cdot2) \cdot(2 \cdot2) \cdot5 } = 2\cdot 2 \cdot 2 \sqrt{5} \]

Answer 7

yes, if you can identify a perfect square right away, that works

Answer 8

however (though it is a bit lazy) we could rule out choices C and D because they do not have an i
and we can rule out choice B because it has a negative, which we do not expect.