Answer: 
a = 9
Explanation:
Step 1: Add 3 to both sides 
2a – 3 = 15 
2a – 3 + 3 = 15 + 3 
Step 2: Simplify 
add the numbers ( 2a = 18 ) 
Step 3: Divide both sides by the same factor 
 2a = 18 
 2a 18
 ––– = –––
 2 2 
Step 4: Simplify 
l
Cancel the terms that are in both the numerator and the denominator 
l
l
Divide the numbers
l 
a = 9 
Answer: a = 9