Question

25. Решите уравнения: а) 5,6а + 1,25а + 3,15a = 2,7; b) 9,18b + 78,4b + 12,42b = 3,5; g) 1,2(2,3x - 3,1)+ 3 = 3,14x - 11: h) 25,34-(y: 2,7 + 1,85) = 12,35.​

Answer 1

а)

$5.6a + 1.25a + 3.15a = 2.7 \\ 5.6a + 4.4a = 2.7 \\ 10a = 2.7 \\ a = 2.7 \div 10 \\ a = 0.27$

b)

$9.18b + 78.4b + 12.42b = 3.5 \\ 21.6b + 78.4b = 3.5 \\ 100b = 3.5 \\ b = 3.5 \div 100 \\ b = 0.035$

g)

$1.2(2.3x - 3.1) + 3 = 3.14 x- 11 \\ 2.76x - 3.72 + 3 = 3.14x - 11 \\ 2.76x - 0.72 = 3.14 x- 11 \\3.14x - 2.76x = 11 - 0.72 \\ 0.38x = 10.28 \\ x = \frac{1028}{38} \\ x = \frac{514}{19} \\ x = 27 \frac{1}{19}$

h)

$25.34 - (y \div 2.7 + 1.85) = 12.35 \\ 25.34 - y \div 2.7 - 1.85 = 12.35 \\ y \div 2.7 = 25.34 - 1.8 5- 12.35 \\ y \div 2.7 = 25.34 - 14.2 \\ y \div 2.7 = 11.14 \\ y = 11.14 \times 2.7 \\ y = 30.078$

Answer 2

Пошаговое объяснение:

5,6а + 1,25а + 3,15а = 2,7

10х = 2,7

х = 2,7 : 10

х = 0,27

9,18в + 78,4в + 12,42в = 3,5

100в = 3,5

в = 3,5 : 100

в = 0,035

1,2(2,3х - 3,1) + 3 = 3,14х - 11

2,76х - 3,72 + 3 = 3,14х - 11

2,76х - 0,72 = 3,14х - 11

2,76х - 3,14х = -11 + 0,72

-0,38х = -10,28

х = -10,28 : (-0,38)

х = 1028/100 * 100/38

х = 1028/38

х = 27 2/38

х = 27 1/19

25,34 - (у : 2,7 + 1,85) = 12,35

у : 2,7 + 1,85 = 25,34 - 12,35

у : 2,7 + 1,85 = 12,99

у : 2,7 = 12,99 - 1,85

у : 2,7 = 11,14

у = 11,14 * 2,7

у = 30,078