Not really sure but 4 and the other - and the 0 so yes.
5≥|4-2x|
5≥4-2x≥-5
-1≤2x≤9
-0.5≤x≤4.5
x∈[-0.5;4.5]
The reciprocal of a number is the number that the first number will multiply with that equals one.
So, for instance, the reciprocal of 3 is 1/3.
Since we can write 3 as 3/1, we can see it's simply flipping the numerator and denominator to find the reciprocal.
So, flipping numerator and denominator, the reciprocal of 31/2 is 2/31.