Answer:
C=30
Step-by-step explanation:
Supposing that we have the lines
x+2=10y
and
3x+6=Yc.
Note that dividing by 3 the second line can be rewritten as
x + 2= Y c/3.
Remember that a line is written as 
, in our case, both lines have 
and 
. Therefore, in orther that the two lines are equal, we need that 
, hence 
3d=12
This should be your equation
And if it is asking for the answer it would be 4
I hope this answer helps!
