B) ¿Durante cuántas décadas ha tenido vigencia la Constitución
de 1917?

The Constitution of 1917, still in force almost 100 years later, has 137 articles. These define citizenship, organize a government, mandate land reform, and enumerate basic human rights for all Mexicans.  

Or in English, the Constitution of 1917, still in force almost 100 years later, has 137 articles. These define citizenship, organize a government, mandate land reform, and enumerate basic human rights for all Mexicans.

- Atargatis Jones

cultural achievements of the 1920's 2010  

1. cultural achievements and african american achievements in the 1920’s  

2. art and literature charles lindberg flew from ny to paris, france. became national hero; first transatlantic flight.  

3. greenwich village (new york) and the south side (chicago)  many artists, writers, and intellectuals flocked to these areas to share ideas  people lead bohemian, or artistic and unconventional, lifestyles

8 - (2a + 7) = a + 40     distribute/multiply - into (2a + 7)

8 - 2a - 7 = a + 40

1 - 2a = a + 40       add 2a on both sides

1 = 3a + 40         subtract 40 on both sides

-39 = 3a       divide 3 on both sides

-13 = a

[proof]

8 - (2a + 7) = a + 40

8 - (2(-13) + 7) = -13 + 40

8 - (-26 + 7) = 27

8 - (-19) = 27

8 + 19 = 27

27 = 27