Answer:
Line 1 Slope: - 4/3
Line 2 Slope: 3/4
Line 3 Slope: 3/4
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Line 1 and Line 2: Perpendicular
Line 1 and Line 3: Perpendicular
Line 2 and Line 3: Parallel
Step-by-step explanation:
Line 1: Passes through (6, -4) and (0, 4).
We first find the slope by using this equation (y2 - y1) / (x2 - x1) -    
(4 - (-4)) / (0 - 6)    
(4 + 4) / (-6)  
8 / -6
-4 / 3  
Slope = - 4/3
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Line 2: Passes through (-4, -2) and (8, 7).
We first find the slope by using this equation (y2 - y1) / (x2 - x1) -    
(7 - (-2)) / (8 - (-4))    
(7 + 2) / (12)  
9 / 12
3 / 4  
Slope = 3/4
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Line 3: Passes through (-4, -5) and (4, 1).
We first find the slope by using this equation (y2 - y1) / (x2 - x1) -    
(1 - (-5)) / (4 - (-4))    
(1 + 5) / (4 + 4)  
6 / 8
3 / 4  
Slope = 3/4
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Line 1 and Line 2: Perpendicular
Line 1 and Line 3: Perpendicular
Line 2 and Line 3: Parallel