The solution equation: 1, X-7 / 3 = 17 / 13.2, 21 / 13-x = 14 / 3 What can be calculated simply: 4-15 / 4-15 / 11=

The solution equation: 1, X-7 / 3 = 17 / 13.2, 21 / 13-x = 14 / 3 What can be calculated simply: 4-15 / 4-15 / 11=

X-3 / 7 = 13 / 17
X = 13 / 17 + 3 / 7
X = 91 / 119 + 51 / 119
X = 142 / 119
13 out of 21-x = 3 out of 14
X = 13 / 21-3 / 14
X = 26 / 42-9 / 42
X = 17 / 42
4-15 / 4-15 / 11
=4 - (4 / 15 + 11 / 15)
=4-1
=3