Respuesta :

Darkling
10a+3+2a=39
12a+3=39
      -3   -3
12a=36
/12   /12
a=3
DarkBeauty
10a+3+2a=39
First simplify
12a+3=39
Then subtract 3 from both sides
12a=36
Then divide both sides by 12
a=3