Question

решите следующее уравнение

Answer 1

0.9(у-4)=0.2(7+5у)
0.9у-3.6=1.4+у
0.9у-у=1.4+3.6
-0.1у=5
у=5:(-0.1)
у=-50

Answer 2

$\frac{0.9}{7 + 5y} = \frac{0.2}{y - 4} \\ 0.9(y - 4) = 0.2 (7 + 5y) \\ 0.9y - 3.6 = 1.4 + y \\ 0.9y - y = 1.4 + 3.6 \\ - 0.1y = 5 \\ y = - 50$