Hi, I don't know if you still need the answer, but here you go:
Answer:
They used distributive property.
Step-by-step explanation:
They multiplied -9/2 times "x" and then, times "+6".
First, you get -9/2x for the first term in the parenthesis.
Second, you multiply -9/2 times 6 in the form of a fraction.
* When multiplying fractions, you multiply straight across so:
-9/2 × 6/1 = -54/2
Leaving you with:
-9/2x-54/2
The -54/2 simplifies into -27, which gives you:
[tex]-\frac{9}{2}x - 27[/tex]