Как решить уравнения1

(39+x) - 84=78

(x-83) + 316=425

(600-x) - 920=126

253 - (X-459) = 138

502 - (217-x) = 421

871 - (x+157) = 385

(39+x) - 84=78

39+х-84=78

х=78-39+84

x=123

(x-83) + 316=425

x-83+316=425

x=425+83-316

x=192

(600-x) - 920=126

600-x-920=120

x=120+920-600

x=440

253 - (X-459) = 138

253-x-459=138

x=138+459-253

x=344

502 - (217-x) = 421

502-217-x=421

x=421+217-500

x = 135

871 - (x+157) = 385

871-x+157=385

1028-x=385

x=1028-385

x=643

(39+х) - 84=78

39+х-84=78

х=78-39+84

х=123

(х-83) + 316=425

х-83+316=425

х=425+83-316

х=192