Please help me fast and fill it in

frederick the great and the war of austrian succession. frederick william of brandenburg-prussia trained his son, frederick, to be a hardy soldier. he also declared himself king of bohemia, and maria theresa sent troops to retake bohemia. in august he led 80,000 of these men across the frontier into bohemia, his

i see, would you mind putting it as one?

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