Answer:
First option.
Third option.
Fourth option.
Step-by-step explanation:
For this exercise is important to remember that equivalent expression have the same value.
Then given the following expression provided in the exercise:
You can find equivalent expression by:
- Changing the position of 
:
(This matches with the first option)
- Solving the multiplication indicated. Then:
(This matches with the fourth option)
- Writting 
inside the parentheses:
(This matches with the third option)
I solved this problem by setting 240/80 equal to x/100 . Once you set them equal to each other, multiply 240 and 100 and divide the product by 80 and you get 300.
So you add all the like terms.......i.e numbers with same variable
so,
5x+9y-7x+2-5y-7x+2-3x
=(5-7-7-3)x+(9-5)y+2+2
=-12x+4y+4
Cost per ounce means you take the cost and divide it by the cost:
<span>3.36 / (21/2) </span>
<span>division of fractions changes to the multiplication of the reciprocal: </span>
<span>3.36 * (2 / 21) </span>
<span>3.36 and has 21 as a factor, so let's cancel it: </span>
<span>0.16 * 2 </span>
<span>$0.32 per ounce</span>
1/5+ (-4) is the same as 1/5 - 4
1/5-20/5
-19/5
