Step-by-step explanation:
3y means 3 times y. It is normally used to shorten an equation with a variable to save room. The number is always placed before the variable.
Observe the given figure.
Given: 
To prove: 
Statement
1. 
Reason: Given
2. 
Reason: Substitution
3.
are alternate interior angles.
Reason: Definition of alternate interior angles
4. 
Reason: If alternate interior angles are equal, then the lines are parallel.
Step-by-step explanation:
mental don't post this type of question
Answer:
D
Step-by-step explanation: