4 = 2²

6 = 2 .3 

8 = 2³

=> BCNN(4;6;8) = 2³ . 3 = 8 .3 = 24

__Good luck__

We have : x - 10 + 2 = 20 + 10 

=> x - 10 + 2 = 30 

=> x - 10 = 30 - 2 

=> x - 10 = 28

=> x = 28 + 10 

=> x = 38

A) 46 + 17 + 54  =  ( 46 + 54 ) + 17  = 100 + 17 = 117

B) 4 . 35 . 25  = (4 . 25) . 35 = 100 . 35 = 3500