(7-8i)x(6+5i)
multiply the second parentheses by each term from the first parentheses
7(6+51)-8ix(6+5i)
distribute 7 through the parentheses
42+35i-8ix (6+5i)
i2 = -1
42+35i-48i-40 x(-1)
any expression multiplied by equals its opposite
42+35i-48i+40
add numbers
82+35i-48i
82-13i