629 - (333-у) = 459

(357 - (у-281)) + 112=402

13*х-9*х-16=27-7

19980: (7*х-15) = 54

629-333+у=459

у=459-629+333

у=163

(357 - (у-281)) + 112=402

(357-у+281) + 112=402

-у+638+112=402

-у=402-112-638

-у=-348

у=348

13 х-9 х-16=27-7

13 х-9 х=27-7+16

4 х=36

х = 36:4

х=9

19980: (7 х-15) = 54

19980:54=7 х-15

370=7 х-15

-7 х=-385

7 х=385

х=385:7

х=55