Respuesta :

clache
-a+7=2a-8
-a+a+7=2a+a-8    add a on both sides
7+8=3a-8+8         add 8 on both sides
15/3=3a/3             divide 3 on both sides
a=5                     solution
1st combine like terms
1a=(-1)
a=(-1) I think thats it