1) 2 1/2X - 1 5/8 = 2 3/4
2.5X - 1.625 = 2.75
2.5X = 4.375
X = 1.75
X = 1 3/4
====================
2) 1/4 + X : 3 5/9 = 7/16
X : 3 5/9 = 7/16 - 1/4 = 7/16 - 4/16 = 3/16
X : 32/9 = 3/16
X = 3/16 * 32/9 = 32/48 = 2/3
X = 2/3
=====================
3) 4 2/5 : X - 2 3/5 = 7/10
4.4 : X = 0.7 + 2.6
4.4 : X = 3.3
X = 4.4 : 3.3
X = 44/33 =1 11/33 = 1 1/3
======================