Question 1066981
Start this way, ultimately to multiply later.


The other root is  3+4i.


{{{(x-(3-4i))(x-(3+4i))=0}}}

Do you understand what to do here?


---No?


Simplify the left member, by working first within the parentheses, and then performing the multiplication, and combine like terms.  Put into "general" form.  You will be able to read "b" and "c" right from the finished equation.


Here is the first step:
{{{(x-3+4i)(x-3-4i)=0}}}


The second step:
{{{((x-3)+4i)((x-3)-4i)=0}}}


Now you should understand the next steps to take and finish.
You do this!