Answer:
, 
Step-by-step explanation:
<h3>
I will use the elimination method.</h3>
We want to make the X's the same:


Because the signs of the X's are the same we subtract the 2 equations to make:
(I put the second one on top of the 1st)

So:

Substitute y into either equation 1 or 2:
(I chose equation 1)



So:

b=16 , First you multiply 30 by 2 to see what sum you need for the numerator. Then you subtract the 60 that you get by the 12 and get 48. So 3 multiplied by b should give you 48. So you just divide 48 by 3 and get 16.
C. a-3x=0
Equations are like a balance scale. There needs to be an “=“
I can give you the equations for the graph. First one would be y = 0.90x + 25 (25 being the y intercept) and the other one would simply be y = 1.35. If you have a graphing calculator like me you can use it when modeling the graph. Hopefully this helps!