Answer:
The slope of FG is -1
Step-by-step explanation:
Given
Square EFGH
EF: 
Required
Determine the slope of FG
First, we calculate the slope of EF

Make y the subject


The general equation has the form: 
Where

Compare
to 

<em>From the name of the square EFGH, we can conclude that EF and FG are perpendicular</em>
<em />
The relationship between perpendicular lines is:

Where
-- Slope of EF
and
m2 = slope of FG
Substitute 1 for m1 in 


<em>Hence, the slope of FG is -1</em>