You can
put this solution on YOUR website!Let

be tha mount at 9%,

the amount at 10%.
Total amount invested:
1.

Total interest received:
2.

Multiply eq. 1 by (-10) and add to eq. 2,

Something is wrong with your numbers because that amount is greater than the total invested amount.
If the entire amount was invested at 10%, the interest would be $2400.
If the entire amount was invested at 9%, the interest would be $2160.
Your interest amount is outside of the possible range.
Check your numbers and re-post.