document.write( "Question 1158321: what numbers multiply to -9 and add to 5
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Algebra.Com's Answer #781238 by Theo(13342)![]() ![]() You can put this solution on YOUR website! let x = one of the numbers and y = the other of the numbers. \n" ); document.write( "you get: \n" ); document.write( "x + y = 5 \n" ); document.write( "x * y = -9 \n" ); document.write( "solve for y in the first equation to get y = 5 - x \n" ); document.write( "replace y with 5 - x in the second equation to get x * (5 - x) = -9 \n" ); document.write( "simplify to get 5x - x^2 = -9 \n" ); document.write( "subtract the left side of the equation from both sides of the equation to get: \n" ); document.write( "5x - x^2 - (5x - x^2) = -9 - (5x - x^2) \n" ); document.write( "simplify to get: \n" ); document.write( "5x - x^2 - 5x + x^2 = 9 - 5x + x^2 \n" ); document.write( "combine like terms to get: \n" ); document.write( "0 = 9 - 5x + x^2 \n" ); document.write( "reorder the terms in descending order of degree to get: \n" ); document.write( "0 = x^2 - 5x - 9 \n" ); document.write( "switch sides to get: \n" ); document.write( "x^2 - 5x - 9 = 0 \n" ); document.write( "solve this quadratic equation using the quadratic formula to get: \n" ); document.write( "x = (-5 + sqrt(61)) / 2 or x = (-5 - sqrt(61)) / 2 \n" ); document.write( "use your calculator to find the decimal equivalent of these values to get: \n" ); document.write( "x = 1.405124838 or x = -6.405124838 \n" ); document.write( "replace x with 1.405124838 in the first equation to get: \n" ); document.write( "1.405124838 + y = 5 \n" ); document.write( "solve for y to get y = -6.405124838 \n" ); document.write( "replace x and y with these values in the second equation to get: \n" ); document.write( "x * y = 1.405124838 * -6.405124838 = -9 \n" ); document.write( "the values are confirmed to be good. \n" ); document.write( "your solution is that one of the numbers is 1.405124838 and the other number is -6.405124838. \n" ); document.write( "the numbers shown are rounded by the calculator to 9 decimal digits. \n" ); document.write( "the actual values have more decimal digits than that. \n" ); document.write( " \n" ); document.write( " |