Which is the best example of a primary source document useful in the study of history

the second world war (wwii) was one of the major trans formative events of the 20th century, with 39 million deaths in europe alone. large amounts of physical capital were destroyed as well through six years of constant ground battles and bombing. many individuals were forced to abandon or give up their property without compensation and to move on to new lands. periods of hunger become more common even in relatively prosperous western europe. families were separated for long periods of time especially from their fathers. many including young children would personally witness the horrors of war as battles and bombing took place in the very areas where they lived. horrendous crimes against humanity were committed. due to wwii, political and economic systems in many countries would be permanently altered.

1.3x - 2 - (3.3x + 5) = 2x + 1

1.3x - 2 - 3.3x - 5 = 2x + 1

-2x - 7 = 2x + 1

-7 = 4x + 1

-8 = 4x

x = -2