how do I find the final product of this kind of problem (2x+6) (x+1)

Use this method called FOIL.

Multiply the First numbers, then multiply to outer numbers, then the inner numbers, then the last numbers.

Then combine the ones that are common.

For Example.

(2x+6)(x+1) =

2x(squared)  + 2x +6x + 6

The final answer being

2x(squared) + 8x + 6

Curses!!!......$*#%$........Foiled, again!!

I often wondered what foil actually stood for. lol.

First, Outer, Inner, last

That makes sense.  Thanks Chris!

Extra points because you taught me something and because I stole the other ones off you!