Question

Afla termenul necunoscut :

3+7x [45-3x(4x a+3)]=3

Answer 1

3+7 [45-3(4a+3)]=3

3+7(45-12a-9)=3

3+7(36-12a)=3

3+252-84a=3

255-84a=3

-84a=3-255

-84a=-252

a=-252/-84=3

a=3

Answer 2

3 + 7 x [ 45 - 3 x ( 4 x a + 3 ) ] = 3

7 x [ 45 - 3 x ( 4 x a + 3 ) ] = 3 - 3 = 0

45 - 3 x ( 4 x a + 3 ) = 0 : 7 = 0

3 x ( 4 x a + 3 ) = 45 - 0 = 45

4 x a + 3 = 45 : 3

4 x a + 3 = 15

4 x a = 15 - 3

4 x a = 12

a = 12 : 4

a = 3

Verific: 3 + 7 x [ 45 - 3 x ( 4 x 3 + 3 ) ] = 3 + 7 x ( 45 - 3 x 15 ) = 3 + 7 x 0 = 3