Respuesta :

abhi569

Answer:

15

Step-by-step explanation:

When b = 9,

=> 3a + 9 = 54

=> 3a + 9 - 9 = 54 - 9

=> 3a = 45

=> 3a/3 = 45/3

=> a = 15

Therefore, when b is 9, a is 15

HatfieN4995

Answer:

a=15

Step-by-step explanation:

First, you will plug in 9.

Then, you'll solve for a: 3a+9=54

Then, you'll subtract 9 from both sides. It will look like this: 3a+9-9=54-9

Then: 3a=45

Then you'll divide: 3a/3=45/3

And it gives you: a=15