Translate the following application into a system of linear equations, but do not solve.
"John invested $12,000 in two accounts, one that earns 7% interest and another that earns 4%. If the total interest earned after one year was $507.90, how much was invested in each account?"
Let amount invested in the 7% and 4% be S and F, respectively
Then we have: S + F = 12,000 ------- eq (i)
We also get: 07S + .04F = 507.9 ---- eq (ii)
That's IT!!
On one hand, your request was NOT to solve, but then a solution was requested after. Which is it?
If you want a solution, you should be able to do that on your own since you have the equations to do so.