Respuesta :

Add 4a to both sides:
8 = 2a
Divide both sides by 2:
a = 8/2
a = 4

Answer:

a = 4

Step-by-step explanation:

So your goal here is to get the variable on just one side, so add 4a to both sides.  This cancels out the 4a on of of the sides and puts a on the other side.  The new equation is 8 = -2a + 4a.  Combine like terms to get 8 = 2a.  Divide both sides by 2 to get a = 4.    You can check your work by replacing a with 4:  

8 - 4(4) = -2(4)

8 - 16 = -8

-8 = -8

Since the final result is true, (-8 does equal -8,) a = 4.