Question 694095
(6-5i)(4-9i) 
Use FOIL:
F: 6*4 = 24
O:6*-91 = -54i
I:-5i*4 = -20i
L:-5i*-9i = -45
------
Combine to get:
-21 -74i
====================

(2+3i)/(4-5i)
----
Multiply numerator and denominator by (4+5i) to get:
-----
= [(2+3i)(4+5i)]/[(4-5i)(4+5i)]
-------
= [8-15 + 21i+10i] / [16+25]
------
= [-7+31i]/41
=====================
Cheers,
Stan H.