SOLUTION: {{{sqrt (-5) (sqrt(15)-sqrt(-15))}}} I need help solving this

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Question 919176: sqrt+%28-5%29+%28sqrt%2815%29-sqrt%28-15%29%29
I need help solving this
Found 2 solutions by stanbon, DrBeeee:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
sqrt(-5)*(sqrt(15)-sqrt(-15)
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= sqrt(-75) - sqrt(-15)
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= 5isqrt(3) - isqrt(15)
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Cheers,
Stan H.
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Answer by DrBeeee(684) About Me  (Show Source):
You can put this solution on YOUR website!
Given:
(1) sqrt%28-5%29%2A%28sqrt%2815%29-sqrt%28-15%29%29
Let's start by simplyfing
(2) sqrt%28-15%29=+sqrt%28-1%2A15%29 or
(3) sqrt%28-15%29=+sqrt%28-1%29%2Asqrt%2815%29 or
(4) sqrt%28-15%29=+i%2Asqrt%2815%29
Now simplify
(5)sqrt%28-5%29=+sqrt%28-1%2A5%29 or
(6)sqrt%28-5%29=+sqrt%28-1%29%2Asqrt%285%29 or
(7)sqrt%28-5%29=+i%2Asqrt%285%29
Now put (4) and (7) into (1) and get
(8)i%2Asqrt%285%29%2A%28sqrt%2815%29-i%2Asqrt%2815%29%29
Factor out sqrt%2815%29 and get
(9)i%2Asqrt%285%29%2Asqrt%2815%29%2A%281-i%29
Now combine sqrt%285%29%2Asqrt%2815%29 to get 5*sqrt(3)
Then (9) reduces to
(10)i%2A5%2Asqrt%283%29%2A%281-i%29
Now multiply in by i and get
(11)5%2Asqrt%283%29%2A%28i-i%5E2%29
Since i^2 = -1, (11) reduces to the final answer
(12)5%2Asqrt%283%29%2A%28i%2B1%29