Hey there!!
How do we solve this?
We substitute the value of 5 instead of x
Given :
f(x) = l -3x - 6 l
f(5) = l -15 - 6 l
f(5) = l -21 l
As the value inside a mod shall always be positive, the required answer is 21
Hence, the required answer is 21
Hope my answer helps!