Solve each equality and express your answer in the form $r =$___

1. The equation $\frac{39}{7} + r = \frac{50}{8}$ has the solution

2. The equation $-\frac{39}{7} - r = -\frac{50}{8}$ has the solution

3. The equation $r - \frac{39}{7} = -\frac{50}{8}$ has the solution

4. The equation $\frac{39}{7} - r = \frac{50}{8}$ has the solution

Hint: