Question 69675
Let x=amount at at 6%
Then $10000-x=amount at 9%

Now we are told that the amount of interest received at 6% (.06x) plus the amount of interest received at 9% (.09(10000-x)) equals $684.  So our equation to solve is:

.06x+.09(10000-x)=684  get rid of parens

.06x+900-.09x=684 subtract 900 from both sides

-.03x=-$216

x=$7200---------------------amount invested at 6%

10000-x=10000-7200=$2800-------------------amount invested at 9%


Ck

.06(7200)+.09(2800)=684

432+252=684

684=684


Hope this helps----ptaylor