X+_=-7 and x+_=-4. Add 7 and 4 to each side to get (x+7) and (x+4). You want to FOIL these next, so (x+7)(x+4) = x^2+4x+7x+28. Now you just need to combine like terms, and BAM. There's your answer.
Answer: 12 men would be needed to repair the same road in 3 1/3 hrs. Inverse proportion because usually in work,food and time its inversly proportional.
