D- this should be correct because it explains the possible way of them matching even though DEF is bigger
So for this, I will be using the substitution method. Firstly, subtract both sides in the second equation by 2x: 
Next, substitute y in the first equation with 7-2x, then solve for x from there:

Now that we got x, substitute it into either equation to solve for y:

In short, x = 1/2 and y = 6.
The total was $1,560 so he paid $210 in finance charges.
1. ratio = 2 c of dressing / 4 lb of vegetables
Use two variables: d for the number of c of dressing and v for the number of pounds of vegetables.
Then d / v = 2/4 = 1/2 => d = v/2
Now you can make a table
v d
2 1
4 2
6 3
8 2
And you can draw a line for the points (2,1); (4,2); (6,3), (8,4) ... the slope of the graph is the ratio = 1/2
b) I already did it above as part ot the explanation: d/v = 1/2