Question

решите уравнение
х/(8100-х)=100/8

Answer 1

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