Question

30 б. умаляю помогите
x-3/7x=2,8 (уравнение)
4 3/7:1/7-1 5/6x3 (умножить)
1/3y+5/9y=7,2
умаляяю

Answer 1

x-3/7x=2,8
4/7х=28/10
х=28/10 : 4/7
х = 28/10 * 7/4 = 49/10 = 4,9

4 3/7:1/7-1 5/6x3 = 31/7 * 7/1 - 11/6 * 3 = 31-11/2 = 31- 1 1/2 = 30 1/2 

1/3y+5/9y=7,2 
3/9у+5/9у=7,2
8/9у=72/10
у=72/10 : 8/9 = 72/10 * 9/8=81/10=8,1

Answer 2

$x - \frac{3}{7} x = 2.8 \\ \\ \frac{4}{7} x = 2.8 \\ \\ x = 2.8 \div \frac{4}{7} \\ \\ x = 4.9$


$4 \frac{3}{7} \div \frac{1}{7} - 1 \frac{5}{6} \times 3 = 25.5 \\ \\ 1)4 \frac{3}{7} \div \frac{1}{7} = 31 \\ \\ 2)1 \frac{5}{6} \times 3 = 5.5 \\ \\ 3)31 - 5.5 = 25.5$


$\frac{1}{3} y + \frac{5}{9} y = 7.2 \\ \\ \frac{8}{9} y = 7.2 \\ \\ y = 7.2 \div \frac{8}{9} \\ \\ y = 8.1$