Let's solve each equation step by step:

(456 + 112) - x = 400
568 - x = 400
Now, let's solve for x:
-x = 400 - 568
-x = -168
x = 168

x - (203 + 303) = 34
x - 506 = 34
Now, let's solve for x:
x = 34 + 506
x = 540

34(283 - x) - 33 = 0
9552 - 34x - 33 = 0
9520 - 34x = 0
Now, let's solve for x:
-34x = -9520
x = 280

(536 + x) - 420 = 116
556 + x - 420 = 116
x + 136 = 116
Now, let's solve for x:
x = 116 - 136
x = -20

437 - (227 + x) = 0
437 - 227 - x = 0
210 - x = 0
Now, let's solve for x:
-x = -210
x = 210

468 - 217 - x = 51
251 - x = 51
Now, let's solve for x:
-x = 51 - 251
-x = -200
x = 200

Therefore, the solutions for x in each equation are: