Question

Afla termenul necunoscut :

2x [3+5x(2x a -1]=56

Answer 1

2 [3+5(2 a -1)]=56

2(3+10a-5)=56

2(10a-2)=56

20a-4=56

20a=56+4

20a=60

a=60/20=3

a=3

Answer 2

2 × [ 3 + 5 × ( 2 × a - 1 ) ] = 56

3 + 5 × ( 2 × a - 1 ) = 56 : 2

3 + 5 × ( 2 × a - 1 ) = 28

5 × ( 2 × a - 1) = 28 - 3

5 × ( 2 × a - 1 ) = 25

2 × a - 1 = 25 : 5

2 × a = 5 + 1

2 × a = 6

a = 6 : 2

a = 3

Verific:

2 x [ 3 + 5 x ( 2 x 3 - 1 )] = 2 x ( 3 + 5 x 5 ) = 2 x 28 = 56