HELPPP PLSSSS ITS ALMOST DUE IN 1 HOUR WILL GIVE BRAINLIEST THANKS AND 5 STARSSS

Answer:
x = 4
Step-by-step explanation:
if one box = 1 then wouldn't a big one be 4 since all you're really doing is placing them together so x+x+x = 12 -1-1 =10 for the left side I'm sure you'll understand the rest