document.write( "Question 320442: two positive integers have a sum of 21 and a product of 108. what are the integers? \n" ); document.write( "
Algebra.Com's Answer #229516 by Sunny Day(15)![]() ![]() ![]() You can put this solution on YOUR website! Let one integer be x \n" ); document.write( "Then the second integer = 21 - x.\r \n" ); document.write( "\n" ); document.write( "Their product = 108 \n" ); document.write( "ie. x(21-x) = 108 \n" ); document.write( "21x - x^2 = 108 \n" ); document.write( "21x - x^2 - 108 = 0 \n" ); document.write( "-x^2 + 21x - 108 = 0 \n" ); document.write( "Multiplying the whole with -1, (in order to make the co-efficient of x^2 +ve)\r \n" ); document.write( "\n" ); document.write( "x^2 - 21x + 108 = 0 -------- (1)\r \n" ); document.write( "\n" ); document.write( "[Now we have to find two numbers such that their product is 108 and sum is -21. and these two numbers will eb factors of 108. They are -9 and -12]\r \n" ); document.write( "\n" ); document.write( "So (1) can be written as \n" ); document.write( "x^2 - 9x - 12x + 108 = 0 \n" ); document.write( "x(x-9) - 12(x-9) = 0 \n" ); document.write( "(x-9) (x-12) = 0 \n" ); document.write( "So either x-9 = 0 or x-12 = 0 \n" ); document.write( " x = 9 or x = 12 \n" ); document.write( "These are the required integers \n" ); document.write( " |