решите уравнение
х/(8100-х)=100/8

х/(8100-х)=100/88*x = 100*(8100 - x)8x = 810000 - 100x8x + 100x = 810000108x = 810000x = 810000:108x = 7500=========или===========х/(8100-х)=100/8x/(8100-x) = 12,5x = 12,5(8100 - x)x = 101250 - 12,5x x + 12,5x= 10125013,5x = 101250x = 101250 : 13,5x = 7500