Question

138/(x+28)=0.1
......................

Answer 1

138 / ( х + 28 ) = 0,1 
х ≠ - 28 
х + 28 = 138 : 0,1 
х + 28 = 1380 
х = 1380 - 28 
х = 1352 
Ответ 1352

Answer 2

138=0.1(х+28)
138=0.1х+2.8
-0.1х=2.8-138
-0.1х=-135.2
х=1352