√(-108)+√(-27) √(-6)∙√(-18)
\[\sqrt{-108} + \sqrt{-27}\] \[\sqrt{-6} * \sqrt{-18}\]
is this 2 different problems ?
@phi I think so.
yes
@phi @vzfreakz
Do you have a scientific calculator? That'd be the easy way. If not, then that's fine.
yes i do
the first thing to do is factor the numbers inside the square root. -108 is 4* -27 \[ \sqrt{ 4 \cdot 27 \cdot -1 } = \sqrt{4} \sqrt{27} i= 2 \sqrt{27} i\]
so the first problem is \[ 2 \sqrt{27} i+ \sqrt{27} i \] which can be simplified. (btw, i is short for sqr(-1) )
how would you simplify
you have 2 of sqr(27) * i plus one more sqr(27)*i how many sqr(27)*i do you have ?
you have 3 of them
\[3i \sqrt{15}\]
?
except the 15 should be 27
oh...that dosnt match any of the answers
are you sure you have the correct question? or we may be dealing with a typo in the question or answer choices. what are the other choices?
question \[\sqrt{-108}+\sqrt{-27}\] \[-3\sqrt{15}\] \[3i \sqrt{15}\] \[9i \sqrt{3}\] \[-9\sqrt{3}\]
ok. so far we have \[ 3 i \sqrt{27} \] we can do more. first, can you factor 27 ?
3,3,3?
yes, 3*3*3 we can simplify a PAIR inside a square root. in other words \[ \sqrt{3\cdot 3 \cdot 3 } = \sqrt{3\cdot3} \cdot \sqrt{3} \]
remember, for any number "a" we can simplify the sqr( a*a) \[ \sqrt{a\cdot a} =a \]
ok
\[3\sqrt{3}\]
@phi
yes, so \[ 3i \sqrt{27} = 3 i \cdot 3 \sqrt{3} \] you can simplify the 3*3 part
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