Let's solve each equation step by step:

1) 71 - (33 + x) = 26

First, simplify the expression inside the parentheses:

71 - 33 - x = 26

Combine like terms:

38 - x = 26

Now, isolate x by subtracting 38 from both sides:

-x = 26 - 38

-x = -12

Multiply both sides by -1 to solve for x:

x = 12

2) -121 - (35 - x) = 50

First, simplify the expression inside the parentheses:

-121 - 35 + x = 50

Combine like terms:

-156 + x = 50

Now, isolate x by adding 156 to both sides:

x = 50 + 156

x = 206

3) (35 - x) - 28 = -47

First, simplify the expression inside the parentheses:

35 - x - 28 = -47

Combine like terms:

7 - x = -47

Now, isolate x by subtracting 7 from both sides:

-x = -47 - 7

-x = -54

Multiply both sides by -1 to solve for x:

x = 54

4) -15 - (21 - x) = -63

First, simplify the expression inside the parentheses:

-15 - 21 + x = -63

Combine like terms:

-36 + x = -63

Now, isolate x by adding 36 to both sides:

x = -63 + 36

x = -27

5) 11 - (-27 + x) = 31

First, simplify the expression inside the parentheses:

11 + 27 - x = 31

Combine like terms:

38 - x = 31

Now, isolate x by subtracting 38 from both sides:

-x = 31 - 38

-x = -7

Multiply both sides by -1 to solve for x:

x = 7