Question 1109966
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<pre>
<U>interest</U> + <U>interest</U>      = <U>total interest</U>


0.08*x   + 0.09*(9000-x) = 750    dollars


0.08x + 810 - 0.09x = 750

-0.01x = 750 - 810 = -60  ====>  x = {{{(-60)/(-0.01)}}} = 6000.


<U>Answer</U>.  $6000 was invested at 8%.  The rest   9000-6000 = 3000 dollars were invested at 9%.


<U>Check</U>.   0.08*6000 + 0.09*3000 = 480 + 270 = 750 dollars.   ! Correct !
</pre>

Solved.


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To see many other similar solved problems on investment, &nbsp;look into the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/coordinate/lessons/Using-systems-of-equations-to-solve-problems-on-investment.lesson>Using systems of equations to solve problems on investment</A>

in this site.


You will find there different approaches &nbsp;(using one equation or a system of two equations in two unknowns), &nbsp;as well as 
different methods of solution to the equations &nbsp;(Substitution, &nbsp;Elimination).


Also, &nbsp;you have this free of charge online textbook in ALGEBRA-I in this site

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson>ALGEBRA-I - YOUR ONLINE TEXTBOOK</A>.


The referred lesson is the part of this online textbook under the topic "<U>Systems of two linear equations in two unknowns</U>".



Save the link to this online textbook together with its description


Free of charge online textbook in ALGEBRA-I
https://www.algebra.com/algebra/homework/quadratic/lessons/ALGEBRA-I-YOUR-ONLINE-TEXTBOOK.lesson


to your archive and use it when it is needed.