b) 25 . 73 + 100 . 4 + 73 . 75
= 73 . ( 25 + 75 ) + 100 . 4
= 73 . 100 + 100 . 4
= 100 . ( 73 + 4 )
= 100 . 77
= 7700
c) ( x - 34 ) . 15 = 0
=> x - 34 = 0 : 15
=> x - 34 = 0
=> x = 0 + 34
=> x = 34
d) 18 . ( x - 16 ) = 18
=> x - 16 = 18 : 18
=> x - 16 = 1
=> x = 1 + 16
=> x = 17