Im not for sure on this but i would say DF is 13
Answer:
w = 2
Step-by-step explanation:
6w + 4w - 9 + 6 = 9w - 7+ 6
6w + 4w - 9w = - 7 + 6 + 9 - 6
w = 2
Making the assumption that your problem looks like this,

we use the distributive property to multiply:
Here's the right way:


Here's the way they want you to do it:



I think it is false, because you can have a contradicting statement to a true statement