Respuesta :

Answer:

The answer is a=4/5b

Step-by-step explanation:

4(a+b)=9a

4a+4b+-9a=9a+-9a

-5a+4b=0

-5a+4b+-4b=0+-4b

-5a=-4b-

-5a/-5=-4b/-5

a=4/5b