Question

Question #6c1f8

Answer 1

`2(10-n)-20` or -2n

Explanation:

The difference between 10 and some number ,n, is 10-n
Twice that is 2(10-n)
If we increase that by -20 we add on -20
Hence `2(10-n)+(-20)`
Or 20-2n-20
Which is -2n