document.write( "Question 174820: adam is 5 year younger than eve. in one year eve will be three times the age of adam was four years ago. how old is adam? how old is eve? \n" ); document.write( "

Algebra.Com's Answer #129888 by actuary(112) $\"\"$ $\"About$

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Let x = Adam's current age
\n" ); document.write( "Let y = Eve's current age\r
\n" ); document.write( "\n" ); document.write( "So currently, x = y-5
\n" ); document.write( "In one year, y+1=3*(x-4)\r
\n" ); document.write( "\n" ); document.write( "Rearranging the equations we have\r
\n" ); document.write( "\n" ); document.write( "-y+x=-5
\n" ); document.write( "y-3*x=-1-12=-13\r
\n" ); document.write( "\n" ); document.write( "So the two equations are\r
\n" ); document.write( "\n" ); document.write( "-y+x=-5 (Equation #1)
\n" ); document.write( "y-3*x=-13 (Equation #2)\r
\n" ); document.write( "\n" ); document.write( "Add the two equations to eliminate \"y\"\r
\n" ); document.write( "\n" ); document.write( "-y+y+x-3*x=-5-13\r
\n" ); document.write( "\n" ); document.write( "-2*x = -18\r
\n" ); document.write( "\n" ); document.write( "Therefore, x = 9\r
\n" ); document.write( "\n" ); document.write( "Substituting x = 9 into equation #2\r
\n" ); document.write( "\n" ); document.write( "y -3*x = -13 (Solve for y)
\n" ); document.write( "y -3*9 = -13 Set x = 9
\n" ); document.write( "y -27 = -13
\n" ); document.write( "Therefore, y=14\r
\n" ); document.write( "\n" ); document.write( "Using the graphical method as a check\r
\n" ); document.write( "\n" ); document.write( " $\"graph%28300%2C300%2C-5%2C20%2C-5%2C20%2Cx%2B5%2C3%2Ax-13%29\"$ \r
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