2x/x-3 - 6/x-3 . i need a step by step explanation ,

When adding/subtracting fractions you need a common denominator, but you already have one, which is x-3.  So in general:

a/c-b/c=(a-b)/c so you just have:

(2x-6)/(x-3)  now if you factor 2 from the numerator

2(x-3)/(x-3)  the (x-3)s cancel out leaving

2

However!  Note that division by zero is undefined, so x cannot equal 3.  (because both original fractions had denominators of x-3)

What this all means is that that expression will equal 2 for all real values of x other than 3.

The correct answer is 7