Answer:
2(n-9)
Step-by-step explanation:
Hi there!
Let "a number" = n.
"The difference" translates to subtraction, so when the question tells us "the difference of a number and 9", it translates to "n-9".
"Twice" means we'll be doubling something. In this case, we're doubling "n-9":
2(n-9)
I hope this helps!
