Номер 85 помогите пожалуиста

1) x:20 = 2:5 x*5 = 20*2 5x=40 x=40:5 x=8 2) x:18 = 7:9 x*9 = 18*7 9x = 126 x = 126:9 x = 14 3) x:18 = 2:3 x*3 = 18*2 3x = 36 x = 36:3 x = 12 4) 6:x = 3:7 x*3 = 6*7 3x = 42 x = 42:3 x = 14 5) 5:9 = 15:x 5*x = 9*15 5x = 135 x = 135:5 x = 27 6) 12:7 = 60:x 12*x = 7*60 12x = 420 x = 420:12 x = 35