Explain if world war 1 was really a world war​

Contemporaries certainly thought it was a world war and called it that. The term "World War" (Weltkrieg) first appeared in Germany in 1914. The French and British referred to the war as "La Grande Guerre" or the "Great War", but also adopted the term "World War" later in the conflict

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