Ican’t remember what distributive property is.

So technically, you multiply the number outside the parentheses (which is 8) by the numbers inside the parentheses. But you have to do whatever the math symbol is. If it's division, divide the number outside to the numbers inside. So in this case, it will be  

1) 8 times 3x which will equal to 24x
2) 8 times 5= 40
3) The last step is to put them together which will be 24x + 40. You can't add them together because one is a number and one is a number with a variable. 
4) Answer=24x+40  (hope this helps)