So all plain numbers can be combined right? 5+3-2+7... you just follow the PEMDAS rules you learned and add them all up. Well all the numbers that are multiplied by a variable like "x" can be combined in the same way. So if 2+3+4-5 = 4, then similarly 2x+3x+4x-5x=4x. So let's look at your problem.
5x+8+3x-x+5 = 6x-3 (1)
Let's call this (1) and let's combine all "like terms" on each side of the equals sign.
Starting with the left:
5x+8+3x-x+5 (Separate the terms with an "x" from the terms without one)
5x+3x-x+8+5 (Now you can simplify the x's and the plain numbers just like we talked about)
5x+3x-x = 7x and 8+5=13.
So the whole left hand side can be written as 7x+13.
7x+13 = 6x-3 (2) Let's call this two.
Now let's look at the right hand side.
6x-3. Well there's nothing more you can do there. You just have two terms, one with an "x" and one without. You're done! Now let's find out just what x is.
So I'm sure you're learned that whatever you do to one side of the equals sign, you have to do to the other. If you subtract 3 from the left, subtract three from the right. If you add one billion to the left, add one billion to the right.
Let's look at (2) again.
7x+13 = 6x-3. Now let's take away 6x from both sides.
7x+13 - 6x = 6x-3 - 6x. Now let's simplify both sides.
(7x-6x) + 13 = (6x-6x) -3
(1x) +13 = 0 - 3
x+13= -3 Almost there!
Can you finish it?