Respuesta :

Hrishii

Answer:

10 units

Step-by-step explanation:

LMNO is a square.

All sides of square are equal

MN = LM

3x + 1 = x + 7

3x - x = 7 - 1

2x = 6

x = 6/2

x = 3

LM = x + 7 = 3 + 7 = 10

LM = 10 units