Respuesta :

Architechtor
Ok...

Here we go: 

5x + 3x = 5x + 15/2
So 8x = 5x + 7.5 (because 3x + 5x = 8x and 15/2 = 7.5)
Then 3x = 7.5
x = 2.5

Get it? 
Vesper02
first combine like terms to get

8x = 5x + 15/2 
-5x   -5x

3x = 7.5     (15/2 = 7.5)
/3     /3

x = 2.5
(5(2.5) + 3(2.5) = 5(2.5) + 7.5     =     12.5 + 7.5 = 12.5 + 7.5      =      20 = 20

3(2.5) = 7.5