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.
Given:
Endpoints of segment AB are A(- 18, 5) and B(- 4, 5).
Point Z is located exactly 1/8 of the distance from A to B.
To find:
The value of the x-coordinate of point Z.
Solution:
Point Z is located exactly 1/8 of the distance from A to B.
AZ:AB=1:8
AZ:ZB = AZ:(AB-AZ)= 1:(8-1) = 1:7
It means point Z divided segment AB in 1:7.
Using section formula, the x coordinate of point Z is





Therefore, the required x-coordinate of point Z is -16.25.
Answer:
Do you still need this one?
Step-by-step explanation:

I am old, so I like to use paper & pencil
Answer:
A because 72 divided by 8 is 9 and Henry earns $12 per hour and mike get $9 per hour so there is a $3 difference
Step-by-step explanation: