cum se rezolva exercitiul acesta?
2+{3+2[4+5(7-x)]}:31=3

Răspuns:

2+{3+2[4+5(7-x)]}:31=3

{3+2[4+5(7-x)]}:31=3-2

3+2[4+5(7-x)]=1·31

2(4+35-5x)=31-3

39-5x=28:2

5x=39-14

x=25:5

x=5

2 + { 3 + 2 × [ 4 + 5 × ( 7 - x ) ] } : 31 = 3

{ 3 + 2 × [ 4 + 5 × ( 7 - x ) ] } : 31 = 3 - 2

{ 3 + 2 × [ 4 + 5 × ( 7 - x ) ] } : 31 = 1

3 + 2 × [ 4 + 5 × ( 7 - x ) ] = 1 × 31

3 + 2 × [ 4 + 5 × ( 7 - x ) ] = 31

2 × [ 4 + 5 × ( 7 - x ) ] = 31 - 3

2 × [ 4 + 5 × ( 7 - x ) ] = 28

4 + 5 × ( 7 - x ) = 28 : 2

4 + 5 × ( 7 - x ) = 14

5 × ( 7 - x ) = 14 - 4

5 × ( 7 - x ) = 10

7 - x = 10 : 5

7 - x = 2

x = 7 - 2

x = 5