So it is really easy to solve firstly we can see how much does the first 10 boxes make which makes around 75$ obviously. Secondly 55$ for the next 10 boxes.
So for now we can simply calculate that we have spent around 130$ which means 20 boxes. The remaining money left is 18$ so we can buy 18/4.5 = 4 only 4 boxes with that money. Hence a total of 24 boxes.
For a line to be parallel it has to have the same slope as the original line. so the slope is 1/2
Dodecahedron is a 3D shape, usually when it ends with hedron it is 3D.
So with this, we will be using proportions. To solve for x, our proportion will be 
Firstly, cross-multiply: 
Next, subtract 36 on both sides: 
Next, replace -9x with 3x-12x 
Next, factor x^2+3x and -12x-36 separately:
. After, rewrite it as 
Next, solve for x separately in the two parentheses:


Since we can't have a negative length, x = 12.
To solve for y, our proportion will be 
Firstly, cross-multiply: 
Next, just square root each side, and your answer will be (rounded to hundredths) 
In short, x = 12 and y = 10.39.