Multiply the two numbers first
6*3= 18
Divide the total volume by 18
144/18=6
Answer: Missing length is 6 ft .
The two at the top technically means how many times the number in the bracket times ITSELF by, so its technically -3 x -3 which is +9 , cause a negative x negative = positive
You are subtracting 3 each time. (-3)
When I multiply it’s is shows 1.53719
II hope this helps it’s pretty simple