Respuesta :
					                   subtract the 1a from the 7a. 
1a + 18 = 7a
-1a -1a
you're then left with 18=6a. divide the 6 with the 18 to cancel out.
18=6a
/6a /6a
18 divided by 6 is 3. So your answer is a=3
					                
					             1a + 18 = 7a
-1a -1a
you're then left with 18=6a. divide the 6 with the 18 to cancel out.
18=6a
/6a /6a
18 divided by 6 is 3. So your answer is a=3
 
			                   
					                  