document.write( "Question 390325: The product of three integers is 90. The second number is twice the first number. The third number is two more than the first number. What are the three numbers? \n" ); document.write( "

Algebra.Com's Answer #276724 by stanbon(75887) $\"\"$ $\"About$

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The product of three integers is 90.
\n" ); document.write( "xyz = 90
\n" ); document.write( "---------------------
\n" ); document.write( "The second number is twice the first number.
\n" ); document.write( "y = 2x
\n" ); document.write( "--------------------------
\n" ); document.write( "The third number is two more than the first number. What are the three numbers?
\n" ); document.write( "z = x+2
\n" ); document.write( "-------------------
\n" ); document.write( "Equation:
\n" ); document.write( "Substitute for y and for z and solve for \"x\":
\n" ); document.write( "x(2x)(x+2) = 90
\n" ); document.write( "2x^3+4x^2-90 = 0
\n" ); document.write( "---
\n" ); document.write( "x^3 + 2x^2 - 45 = 0
\n" ); document.write( "---
\n" ); document.write( "I graphed the cubic and found a solution at x = 3
\n" ); document.write( "Then y = 2x = 6
\n" ); document.write( "And z = x+2 = 5
\n" ); document.write( "---
\n" ); document.write( "Check:
\n" ); document.write( "3*6*5 = 90
\n" ); document.write( "90 = 90
\n" ); document.write( "==========
\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H. \n" ); document.write( "

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