Answer:
A
Step-by-step explanation:
A is the less complicated one and the simplest but also the most efficient and the one that makes the most sense.
There are 31 days in january
Simple, since you want to find y, in y=mx+b form, move everything to the other side.
1/2x-y=4
Move 1/2x
1/2x-y=4
-1/2x -1/2x
Making it look like,
-y=4-1/2x
Divide by the negative 1 in front of the y,
-y=4-1/2x
/-1 /-1
y=-4+1/2x
or
y=1/2x-4
Thus, this written in y=mx+b form, y=1/2x-4.
I thought this might be easier to answer and show the work using a pic