Simplify the expression The root of negative nine over the quantity of three minus two i plus the quantity of one plus five i. .
please can you write your expression using the editor?
\[(\sqrt{-9})\div(3-2i) + (1+5i)\]
here we can rewrite your expression as follows: \[\Large \frac{{\sqrt { - 9} }}{{3 - 2i}} + 1 + 5i = \frac{{3i\left( {3 + 2i} \right)}}{{9 + 4}} + 1 + 5i\]
@jordynhazan1
so that simplifies to \[\frac{ 9i+6i }{ 13 } +1 +5i\]
right?
no, the simplified expression is: \[\Large \begin{gathered} \frac{{\sqrt { - 9} }}{{3 - 2i}} + 1 + 5i = \frac{{3i\left( {3 + 2i} \right)}}{{9 + 4}} + 1 + 5i = \hfill \\ \hfill \\ = \frac{{9i - 6}}{{13}} + 1 + 5i \hfill \\ \end{gathered} \]
am I right?
please remember that: \[\Large {i^2} = - 1\]
furthermore, I have used this identity: \[\Large \frac{1}{z} = \frac{{{z^*}}}{{{{\left| z \right|}^2}}}\] where z* is the complex conjugate of z
i still have to solve for a number but don't know how to
how do i add the 1 and the 5i to the equation
we have to compute the least common multiple, which is 13, so we can write: \[\Large \begin{gathered} \frac{{\sqrt { - 9} }}{{3 - 2i}} + 1 + 5i = \frac{{3i\left( {3 + 2i} \right)}}{{9 + 4}} + 1 + 5i = \hfill \\ \hfill \\ = \frac{{9i - 6}}{{13}} + 1 + 5i = \frac{{9i - 6 + 13\left( {1 + 5i} \right)}}{{13}} = ... \hfill \\ \end{gathered} \]
please simplify
hint: \[\Large \begin{gathered} \frac{{\sqrt { - 9} }}{{3 - 2i}} + 1 + 5i = \frac{{3i\left( {3 + 2i} \right)}}{{9 + 4}} + 1 + 5i = \hfill \\ \hfill \\ = \frac{{9i - 6}}{{13}} + 1 + 5i = \frac{{9i - 6 + 13\left( {1 + 5i} \right)}}{{13}} = \hfill \\ \hfill \\ = \frac{{9i - 6 + 13 + 65i}}{{13}} = ... \hfill \\ \end{gathered} \]
then it becomes \[\frac{ 74i + 7}{ 13 }\]
ok! that's right!
but that isn't near the answers given
Please wait I'm checking my computation
sorry your starting expression, at initial post, is different
no problem we restart to compute the right expression
here is the first step: \[\Large \frac{{\sqrt { - 9} }}{{3 - 2i + 1 + 5i}} = \frac{{3i}}{{4 + 3i}}\]
now we can write this: \[\Large \frac{1}{{4 + 3i}} = \frac{{4 - 3i}}{{16 + 9}}\] since I have used this identity: \[\Large \frac{1}{z} = \frac{{{z^*}}}{{{{\left| z \right|}^2}}}\]
the bottom simplifies to 25
ok! substituting into the above expression, we get: \[\Large \begin{gathered} \frac{{\sqrt { - 9} }}{{3 - 2i + 1 + 5i}} = \frac{{3i}}{{4 + 3i}} = \hfill \\ \hfill \\ = \frac{{3i\left( {4 - 3i} \right)}}{{16 + 9}} \hfill \\ \end{gathered} \]
the answer is C!!
or: \[\Large \begin{gathered} \frac{{\sqrt { - 9} }}{{3 - 2i + 1 + 5i}} = \frac{{3i}}{{4 + 3i}} = \hfill \\ \hfill \\ = \frac{{3i\left( {4 - 3i} \right)}}{{16 + 9}} = \frac{{3i\left( {4 - 3i} \right)}}{{25}} = ... \hfill \\ \end{gathered} \]
\[\frac{ 9 + 12i }{ }\]
that's right! It is option C
over 25
thank you so much
:)
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