1) 5 5/6 ÷ 3 1/2= x/15
25/6 ÷ 3/2 = x/15
25/9 = x/15
375= 9x
x = 125/3 = 41 2/3
2) x/16 = 3 3/4 ÷ 6 2/3
x/16 = 9/4 ÷2×2
x/16= 9/16
x= 9
3) -0,2x ×(-0,7) = 0.84
0.14x = 0.84
x= 6
4) 1/3x + 2 2/5 = 3 2/5
1/3x + 4/5 = 6/5
5x +12 = 18
5x = 18 -12
5x= 6
x= 6/5= 1 1/5= 1.2