5x+2y=100. lg x - lg y = lg 16-1

lg x - lg y = lg 16 - 1 = lg 16 - lg 10lg (x/y) = lg (16/10) = lg (8/5)x/y = 8/5x = 8y/5Подставляем в 1 уравнение5*8y/5 + 2y = 1008y+2y=10y=100y=100/10=10x=8y/5=80/5=16