Answer:
Sorry i have forgotten about this, sorry i couldn't answer this
I wasn't going to click on this one, but the all-caps enthralled me and hypnotized me.
first off, let's change all the mixed fractions to "improper" and proceed from there, keep in mind that if we subtract the two bags' weight from the total, what's leftover is the 3rd bag's weight.

X^2 + 4x + 8 = 0
( x + 2 ) ( x + 2 ) = 0
i am a mathematics teacher. if anything to ask please pm me
The length of a side is 18.
Here is my work attached:
The top one because each one represents a term so 4 is one term and x is another term.
Hoped this helped<span />