A force of 16
N does 120 J of work on an object. Over what displacement did this
force work?
force: F = 16 N
work: W = 120 J
Starting formula 

Algebra: Divide each side by F 

Algebra: Cancel F's on right side 

Algebra: Switch left and right sides 

Plug in numbers with units 

Divide: 120 / 16 = 7.5 

Final result with significant figures and unit 