document.write( "Question 169402: Lin Hisa plans to invest $1,400 in two stocks: Consolidated Industries (CI) and Amalgamated Manufacturing (AM). Suppose that after 5 years Lin's CI stock does not change in value, but her AM stock triples, making her stocks worth $3,300. Write an equation that expresses this fact. \n" ); document.write( "
Algebra.Com's Answer #124920 by gonzo(654)\"\" \"About 
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let x = amount of money invested in CI today
\n" ); document.write( "let y = amount of money invested in AM today.
\n" ); document.write( "-----
\n" ); document.write( "total invested in both equals $1400.
\n" ); document.write( "x + y = $1400
\n" ); document.write( "-----
\n" ); document.write( "5 years from now CI stock doesn't change in value.
\n" ); document.write( "5 years from now AM stock triples.
\n" ); document.write( "total value of both stocks in 5 years is $3300.
\n" ); document.write( "x + 3y = $3300
\n" ); document.write( "-----
\n" ); document.write( "you have two equations that you want to solve simultaneously.
\n" ); document.write( "x + y = 1400
\n" ); document.write( "x + 3y = 3300
\n" ); document.write( "-----
\n" ); document.write( "if you subtract the second equation from the firsts equation, the unknown variable of x will disappear.
\n" ); document.write( "you get:
\n" ); document.write( "(x - x) + (3y - y) = (3300 - 1400)
\n" ); document.write( "this becomes:
\n" ); document.write( "2y = 1900
\n" ); document.write( "y = 950
\n" ); document.write( "-----
\n" ); document.write( "substituting 950 for y in the first equation gets:
\n" ); document.write( "x + 950 = 1400
\n" ); document.write( "subtract 950 from both sides of the equation to get:
\n" ); document.write( "x = 1400 - 950
\n" ); document.write( "which becomes:
\n" ); document.write( "x = 450.
\n" ); document.write( "-----
\n" ); document.write( "you now have a value for x and y that should be able to satisfy both equations.
\n" ); document.write( "-----
\n" ); document.write( "first equation has already been satisfied since that is the equation where we solved for x.
\n" ); document.write( "-----
\n" ); document.write( "second equation is:
\n" ); document.write( "x + 3y = 3300
\n" ); document.write( "substituting 450 for x and 950 for y, we get:
\n" ); document.write( "450 + (3*950) = 3300
\n" ); document.write( "simplifying:
\n" ); document.write( "450 + 2850 = 3300
\n" ); document.write( "3300 = 3300
\n" ); document.write( "equation is satisfied.
\n" ); document.write( "-----
\n" ); document.write( "answer is:
\n" ); document.write( "x = amount invested in CI stock = $450
\n" ); document.write( "y = amount invested in AM stock = $950
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