Answer :

To determine which algebraic expression is a difference with two terms, let's analyze each option in detail:

1. Option A: [tex]\( 9x \div 6 \)[/tex]
- This is a division expression. It does not represent a difference (subtraction) and does not have two terms separated by a minus sign.

2. Option B: [tex]\( 6(x + 5) \)[/tex]
- This expression involves multiplication and can be expanded using the distributive property to [tex]\( 6x + 30 \)[/tex]. It is a sum, not a difference.

3. Option C: [tex]\( 6 + x - 9 \)[/tex]
- This expression consists of three terms: [tex]\( 6 \)[/tex], [tex]\( x \)[/tex], and [tex]\( -9 \)[/tex]. While it does include a subtraction operation, it is not a simple difference with only two terms.

4. Option D: [tex]\( 6x - 9 \)[/tex]
- This expression contains two terms: [tex]\( 6x \)[/tex] and [tex]\( -9 \)[/tex], separated by a minus sign. Therefore, it represents a difference with exactly two terms.

After analyzing all the options, we can conclude that the algebraic expression that is a difference with two terms is:

Option D: [tex]\( 6x - 9 \)[/tex]