Answer:MN = 4 units
Step-by-step explanation:1- getting the value of m:We are given that:NQ = 4m and NQ = 12
This means that:12 = 4m

m = 3
2- getting MQ:We are given that:MQ = 5m + 1
We have calculated that:m = 3
Therefore:MQ = 5(3) + 1 = 15 + 1 = 16 units
3- getting MN:We are given that point N is located somewhere between points M and Q.
This means that:line MQ can be divided into two portions: MN and NQ
This also means that:length of MQ = length of MN + length of NQ
We have calculated that:MQ = 16 units
We are given that:NQ = 12 units
Therefore:16 = length of MN + 12
length of MN = 16 - 12
length of MN = 4 units
Hope this helps :)