document.write( "Question 848415: two numbers have the sum of one and a sum of cubes 31. what is the product? \n" ); document.write( "
Algebra.Com's Answer #511068 by ankor@dixie-net.com(22740)![]() ![]() You can put this solution on YOUR website! two numbers have the sum of one \n" ); document.write( "a + b = 1 \n" ); document.write( "a = (1-b) \n" ); document.write( "and a sum of cubes 31. \n" ); document.write( "a^3 + b^3 = 31 \n" ); document.write( "replace a with (1-b) \n" ); document.write( "(1-b)^3 + b^3 = 31 \n" ); document.write( "FOIL (1-b)(1-b)(1-b) = 1 - 3b + 3b^2 - b^3 \n" ); document.write( "1 - 3b + 3b^2 - b^3 + b^3 = 31 \n" ); document.write( "a quadratic equation \n" ); document.write( "3b^2 - 3b + 1 - 31 = 0 \n" ); document.write( "3b^2 - 3b - 30 = 0 \n" ); document.write( "using the quadratic formula, I got: \n" ); document.write( "b = -2.70156212 then a = 3.70156212 \n" ); document.write( "or \n" ); document.write( "b = 3.70156212 then a = -2.70156212 \n" ); document.write( ": \n" ); document.write( "what is the product? \n" ); document.write( "-2.70156212 * 3.70156212 = -10 \n" ); document.write( " |