Yes, that's correct. The real part is -5, and the 6 is the imaginary part.
The following is quoted from Wikipedia:
"Although other notations can be used, complex numbers are very often written
in the form
where a and b are real numbers, and i is the imaginary unit, which has the
property
. The real number a is called the real part of the
complex number, and the real number b is the imaginary part."