(1/4 + 1/5) x = 1 4/5
1/4 + 1/5 = 9/20
9/20 • x = 1 4/5
X = 1 4/5 : 9/20 = 9/5 : 9/20 = 4
x = 4
(3 1/8 + 1 3/4) x = 2 1/6
3 1/8 + 1 3/4 = 4 7/8
4 7/8 • x = 2 1/6
x = 2 1/6 : 4 7/8 = 4/9
X = 4/9
(2 1/12 - 1 5/6) x = 3/4
2 1/12 - 1 5/6 = 3/12
3/12 • x = 3/4
x = 3/4 : 3/12 = 3
X = 3