There are two ways to solve problems like this. One way is to work them in the usual fashion, doing the necessary arithmetic with fractions and mixed numbers as required. The other way is to multiply the equations by a number that eliminates fractions, then solve the problem in the usual way. Here, we'll use the latter approach.
2) Multiply by 2 to eliminate fractions.
... 22 = x + 6
... 16 = x . . . . . . subtract 6
4) Multiply by 40 to eliminate fractions.
... 91 = -10x +72
... 19 = -10x . . . . . subtract 72
... -1.9 = x . . . . . . divide by -10
As a mixed number, x = -1 9/10