Question 225520
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Let *[tex \Large x] represent the amount invested at 7%.  Then the amount invested at 9% must be *[tex \Large 8000-x].  The amount of interest earned on the 7% investment is then *[tex \Large 0.07x] and the amount earned on the 9% investment is *[tex \Large 0.09(8000-x)].  The sum of these two amounts earned is $660, so:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ 0.07x\ +\ 0.09(8000-x)\ =\ 660]


Solve for *[tex \Large x] to get the amount at 7% and subtract that amount from 8000 to get the other amount.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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