Respuesta :

mhanifa

Answer:

15

Step-by-step explanation:

1. 1/2(a+3)-b=-6  ⇒ a+3-2b= -12 ⇒ a-2b= -15

2. 3a-2b= -5

subtract the equations  to eliminate 2b:

  • 3a+5= a+15
  • 2a= 10
  • a= 5

then

  • b= 10

then

  • a+b= 5+10= 15