Answer:
FM & MG = 21
Step-by-step explanation:
Given that M is the midpoint of FG, that means it splits it into 2 congruent lengths. Therefore if [tex]FM=8a+1[/tex], then the other half has the same value. I can create a equation now because both of them should add up to 42
[tex]8a+1+8a+1=42\\16a+2=42\\16a=40\\a=\frac{40}{16}\\ a=\frac{5}{2}[/tex]
Now that I have a, I can plug that in to [tex]8a+1[/tex] to find both values. You should get that both of them are 21.
Hope that helps!