помогите безотлагательно нужен номер 21

1) 45*7 - 23*7 = 7(45 - 23) = 7*22 = 154;

2) 38*9 - 9*17 = 9(38 - 17) = 9*21 = 189

3) 2*75*5 = (2*5) *75 = 10*75 = 750

4) 6*4*4*5 = (6*4)*(4*5) = 24*20 = 480

5) 8*6*5*125 = (8*125)*(6*5) = 1000*30 = 30 000

6) 9*2*50*3 = (2*50)*(9*3) = 100*27 = 2700

45*7-23*7= 154

38*9-9*17=189

2*75*5=750

6*4*4*5=480

8*6*5*125=30000

9*2*50*3=2700