Hello there!
8m² - 4(7m³ + 5n²)
You wanna start by using the distributive property
=8n² - (-4)(7m³) + (-4)(5n²)
= 8n² - 28m³ - 20n²
= -28m³ - 12m²
There's no way to know this without knowing the number of pencils he started with
We can set up an equation with x as the price of one cup:
4x=0.96
x=0.96/4=0.24
Each cup is $0.24
Hope this helped!
For the first part:Every shirt she grabs, will cost her dollars, so if she grabs 3 shirts, then the cost of the shirts is:

With the same rationale, if she grabs 2 pairs of jeans, the cost of the jeans is:

So, her total is:

If you subtract 3 from the total, then the expression is:
For the second part:If she's paying 3 less for each shirt, then the cost of 3 shirts will become:

In the same fashion, for the two jeans:

So the expression for the total cost is:
For number three:The amounts are different because the cost of the total purchase is different than the cost of each element that makes up the total purchase.
For number four:If you're the owner, you want to give the smallest amount of discount (the one in part 1/a).
So you could clarify by saying there's 3 dollars of the TOTAL purchase's cost.