The answer would be D, 11 units! :)
Answer:
a=2;b=4;c=6.
Louis wrote the correct answer.
It does match-
The Y-Intercept is 12
And the slope is -3/1
You can confirm this by counting rise over run in the graph
Starting at the Y-Intercept (Y=12) the graph goes down 3 units (-3) over 1 unit (1)
This confirms that the slope is -3/1
