1) 1519 - (x + 616) = 488
1519 - x - 616 = 488
903 - x = 488
x = 903 - 488
x = 415
2) (10161 - x) - 2165 = 4018
10161 - x = 4018 + 2165
10161 - x = 6183
x = 10161 - 6183
x = 3978
3) (x + 2316) + 3188 = 9873
x + 2316 + 3188 = 9873
x + 5504 = 9873
x = 9873 - 5504
x = 4369
4) (x - 2515) + 6165 = 8973
x - 2515 = 8973 - 6165
x - 2515 = 2808
x = 2808 + 2515
x = 5323
5) 3132 + (8332 - x) = 6678
8332 - x = 6678 - 3132
8332 - x = 3546
x = 8332 - 3546
x = 4786
6) (6142 + x) - 2183 = 8972
6142 + x = 8972 + 2183
6142 + x = 11155
x = 11155 - 6142
x = 5013