Реши уравнения, используя правило весов 1) 1,5 а-3=а+7,5

2) 1,8b=3 (b-0,12)

1,5 а-3=а+7,5

1,5-а=7,5+3

0,5 а=10,5

а=10,5:0,5

а=21

1,8b=3 (b-0.12)

1.8b=3b-0.36

1.8b-3b=-0.36

-1.2b=-0.36

-b=-0.36:1.2

-b=-0.3

b=0.3

1,5 а - 3 = а + 7,5 | - a

1.5a - a - 3 = a-a + 7.5

0.5a - 3 = 7.5 | + 3

0.5 a - 3 + 3 = 7.5 + 3

0.5 a = 10.5 | : 0.5

a = 10.5 : 0.5

a = 105 : 5

a = 21

1.8b = 3 (b-0.12)

1.8b = 3b - 0.36 | - 1.8b

1.8 b - 1.8b = 3 b - 1.8b - 0.36

0 = 1.2b - 0.36 | + 0.36

0+0.36 = 1.2b - 0.36 + 0.36

0.36 = 1.2b | : 1.2

0.36 : 1.2 = 1.2 b : 1.2

3.6:12 = b

b = 0.3