[tex]\tt Step-by-step~explanation:[/tex]
Since we have to write an expression, it will not have an equal sign.
[tex]\tt Steps:[/tex]
LM is 3x + 5 and LN is 6x + 10. We can assume that M is the midpoint of LN because if you plug in several numbers for x (I'll do 0 and 1), we can see that LM is half the value of LN.
[tex]\tt 3(0)+5=5\\6(0)+10=10\\5~is~half~of~10,~so~that~means~MN~is~congruent~to~LM.[/tex]
[tex]\tt 3(1)+5=8\\6(1)+10=16\\8~is~half~of~16,~so~that~means~MN~is~congruent~to~LM.[/tex]
*
[tex]\large\boxed{\tt Our~final~answer:~MN=3x+5}[/tex]
*Congruent = Same shape and size
