To make the equation easier so that you don't have to use fractions.
The last one because its a side length if 26 inches so you spit in half
You divid the two numbers on top to equal the bottom and the factor one out
Answer:
(-1,-1)
Step-by-step explanation:
Midpoint equation: 
= 
= 
=(-1,-1)
Use the formula and plug it in :)
The answer is 8%.................