Geometry

Question Analysis:  
This is another example of applying a single pair of opposite sides, checking for equality to form a parallelogram.  
The main focus is on setting the expressions equal.

Key Concept Explanation:  
One pair of opposite sides being both parallel and equal ensures the shape is a parallelogram.

Step-by-Step Solution:  
Set the given equal:  4x - 7 = x + 11
Subtract x:  3x - 7 = 11
Add 7:  3x = 18
Divide:  x = 6

Common Mistakes: &...