Why were the 1920s called the Roaring Twenties?
a.
It was an era of sweeping change and new forms of entertainment.
b.
The 1920s were an angry time in which the bear market on Wall Street roared.
c.
The economy grew quickly, fueled by women’s desires for the latest fads.
d.
The New York Twenty, a group of 20 organized crime bosses, monopolized the nation’s bootleg liquor.

a.

It was an era of sweeping change and new forms of entertainment.

Explanation:

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