Question 574171
simplify the following : 
(10+15i)-(48-30i) = (10-48)+(15+30)i = -38+45i
----------------------------------------------------
and
(6-4i)(6+4i) = 36 + 24i -24i +16 = 52
--------------------------------------------
and
(4+3i)(2-5i) = 8 -20i + 6i +15 = 23 -14i
============================================
cheers,
Stan H.