Three individuals form a partnership and agree to divide the profits equally. x invests $9,000. y invests $7,000, z invests $4000. if the profits are $4,800, how much less does x receive than if the profits were divided in proportion to the amount invested?

First you want to know the profits of the three ppl. so: 
4800/3=1600
then u make an equation with proportions: 9x+7y+4x=4800
add the invests: 9+7+4=20x and 4800 would stay same. 
then divide 20 by 4800 to get 240 
now plug the investments to 240 
9 times 240 is 2160 
7 times 240 1680 
4 times 240 is 960
last you must subtract to find x as the investments 
take 1600 and subtract it by 2160 and you get x=560 
$560 is your answer 
hope i helped :D