Answer:
1. 30x + 20
2. -10x + 60
Step-by-step explanation:
The sale price after both markdowns will be $336
<em><u>Explanation</u></em>
The selling price of an item is $600. After 6 months of not selling, it is marked down by 30%
So, the marked down amount after 6 months 
and the selling price after first 6 months will be: 
After another 6 months of not selling , it is further marked down by 20%. So, the marked down amount now 
Thus, the final selling price after all markdowns 
Answer:
x=2.125
y=0
C=19.125
Step-by-step explanation:
To solve this problem we can use a graphical method, we start first noticing the restrictions
and
, which restricts the solution to be in the positive quadrant. Then we plot the first restriction
shown in purple, then we can plot the second one
shown in the second plot in green.
The intersection of all three restrictions is plotted in white on the third plot. The intersection points are also marked.
So restrictions intersect on (0,0), (0,1.7) and (2.215,0). Replacing these coordinates on the objective function we get C=0, C=11.9, and C=19.125 respectively. So The function is maximized at (2.215,0) with C=19.125.
C
I believe is the right one