How to solve these equations? It's multiple choice

The first one is:

78 = -2(m + 3) + m
a) -28
b) -42
c) -72
d) -84

And there's:

-1/3m - 7 = 5
a) -4
b) -15
c) -36
d) 6

I have no idea how to do this ._. 10 pts

1. Distribute the 2:
78 = -2m-6+m, then combine like terms:
84= -m
-84 = m

2. -1/3m = 12
m = -36

or, if it's ever on a test or anything and you're desperate, you can always just work backwards by plugging the answer choices in for "m" (or whatever letter), until one works out.

78 = -2(m + 3) + m
78 = -2m - 6 + m
78 = -m - 6
78 + 6 = -m
m = -84 (d)

-1/3m - 7 = 5
-1/3m = 5 + 7
1/3m = -12
m = -36 (c)

I am taking TRIG in my High School right now and so this is EASY for me:)
the first one is D.)
the second one is A.)

I PROMISE this is the correct answer! I am a top student and on advanced diploma!:)

78=-2m-6+m
78=-m-6
84=-m
=-84

-1/3m-7=5
-1/3m=12
-3/1*-1/3m=12/1*-3/1
=-36