1) (6 * 55) / 11 = x
x = (6 * 55) / 11 = 6*5 = 30
2) 3 / (8*45) = 1/x
1 / (8*15) = 1/x
1/120 = 1/x
x = 120
3) x = (15*24)/90
x = (3*5*3*8)/90
x = (5*8)/10
x = 8/2
x = 4
4) 1/x = 104/(117*8)
1/x = 52/(117*4)
1/x = 13/117
117/13 = x
x = 117/13
x = 9
5) x = (19,5*2)/3
x = 39/3
x = 13
6)1/x = 7/(37,8*15)
1/x = 1/(5,4*15)
81 = x
x = 81