Answer:
x=175
Step-by-step explanation:
What's happening is that every subtraction can be written as "addition of the opposite."
18-5 = 18 + (-5)
One reason this is done in the work you showed is that they're trying to show why you distribute the negative and the 1 into the parentheses, why you multiply everything in the parentheses by "-1" and not just 1.
The other reason is to later to be able to move the individual terms around, so you'll be able to combine like terms.
When you move terms around, the sign has to stay attached to the term, so writing all the subtractions as addition helps keep the sign attached.
Answer:

Step-by-step explanation:

9514 1404 393
Answer:
Either of ...
- (x, y) ⇒ (-x, -y)
- Rotation 180° about the origin
Step-by-step explanation:
There are at least two ways to express the transformation that maps each coordinate to its opposite.
1. reflection across the origin: (x, y) ⇒ (-x,-y)
2. rotation 180° (either direction) about the origin.
Take your pick.
Answer:
C
Step-by-step explanation:
I don't know for sure, but I am pretty sure this is it.