document.write( "Question 971766: Every two years the value of a $225 investment at CIBC grows by $50. At RBC, a $150 investment grows by $90 every 3 years. Use a graphical method to determine when the investments are worth the same value. \n" ); document.write( "
Algebra.Com's Answer #594214 by ankor@dixie-net.com(22740)\"\" \"About 
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Every two years the value of a $225 investment at CIBC grows by $50.
\n" ); document.write( " At RBC, a $150 investment grows by $90 every 3 years.
\n" ); document.write( " Use a graphical method to determine when the investments are worth the same value.
\n" ); document.write( ":
\n" ); document.write( "Assume the 1st investments will grows $25 a yr, the 2nd investment by $30 a yr
\n" ); document.write( ":
\n" ); document.write( "Let x = no. of yrs invested
\n" ); document.write( "let y = accumulated value of the investments
\n" ); document.write( ":
\n" ); document.write( "Write an equation for each
\n" ); document.write( "y = 25x + 225
\n" ); document.write( "and
\n" ); document.write( "y = 30x + 150
\n" ); document.write( ":
\n" ); document.write( "plot these two equations
\n" ); document.write( "\"+graph%28+300%2C+200%2C+-6%2C+25%2C+-100%2C+1000%2C+25x%2B225%2C+30x%2B150%29+\"
\n" ); document.write( "Looks like they intersect at x = 15, y looks like $600
\n" ); document.write( ":
\n" ); document.write( "you can confirm the point of intersection using the equations
\n" ); document.write( "30x + 150 = 25x + 225
\n" ); document.write( "30x - 25x = 225 - 150
\n" ); document.write( "5x = 75
\n" ); document.write( "x = 75/5
\n" ); document.write( "x = 15 yrs they will be equal
\n" ); document.write( ":
\n" ); document.write( "Their value then
\n" ); document.write( "y = 25(15) + 225
\n" ); document.write( "y = $600
\n" ); document.write( "the same with the other equation
\n" ); document.write( "y = 30(15) + 150
\n" ); document.write( "y = $600
\n" ); document.write( " \n" ); document.write( "
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