squareroot-15 squareroot-4 simplify using i

Question

goldeverything · Answer

what is the question?

anonymous · Answer

$$\sqrt{-15} \sqrt{-4}$$ simplify using i

goldeverything · Answer

ohhh ok

anonymous · Answer

root (15) i * 2i, as i is root(-1)

anonymous · Answer

I'm lost.. I don't understand i

anonymous · Answer

"i" is used in complex numbers to stand for "-1" as normally you can square root a negative number you use it to make it "positive" in a sense
so $$\sqrt{-15}=\sqrt{15i ^{2}}$$

anonymous · Answer

so $$\sqrt{15i} \sqrt{4i}?$$

anonymous · Answer

@GoldEverything help.. lol

goldeverything · Answer

i will try to help

anonymous · Answer

Thank you(:

goldeverything · Answer

one second a bad song came on i have to change it

anonymous · Answer

lol okay

anonymous · Answer

now i'm lost

anonymous · Answer

sorry i meant "i" is $$\sqrt{-1}$$

anonymous · Answer

i^2 = -1

so when you square root a negative number, just tack on an i with it

for example

$$\sqrt{-4} = 2i$$

anonymous · Answer

sorry for all those mistakes on my side

anonymous · Answer

so what about the -15?

goldeverything · Answer

ok so basically its 15 square root and the you sqare 15 beacuse it was negative

anonymous · Answer

soooo $$\sqrt{15}\sqrt{4}?$$

anonymous · Answer

you can't factor the square root of 15, so just bring out an i$$\sqrt{-15} = i \sqrt{15}$$

anonymous · Answer

Then how do I put this together??

goldeverything · Answer

im not that great with this equation

anonymous · Answer

It's like chinese to me. Lol

anonymous · Answer

$$\sqrt{-4} = 2i $$
$$\sqrt{-15} = i \sqrt{15}$$

$$i \sqrt{15}*2i = 2i^{2}\sqrt{15}$$

$$i^{2} = -1$$

$$2i^{2}\sqrt{15}=2(-1)\sqrt{15} = -2\sqrt{15}$$

anonymous · Answer

How do you know all this robz8?

anonymous · Answer

practice :)

goldeverything · Answer

funny thing is a can speak chinese @Saralynnjane

anonymous · Answer

Youre my new math person. Lol. And @GoldEverything That's awesome! I can speak a little polish.

goldeverything · Answer

i can speak some too not much though

anonymous · Answer

Where are you from then?

goldeverything · Answer

i was born in us but my mom and i have moved around alot in asia then we came back

anonymous · Answer

Ohhh. that explains a lot! Ive only lived in the usa.

goldeverything · Answer

yeah i learned most of those for school

anonymous · Answer

Military bases?

goldeverything · Answer

no

anonymous · Answer

hmmm okay

goldeverything · Answer

just normal places in asia

goldeverything · Answer

how much polish do you speak

anonymous · Answer

not very well lol