document.write( "Question 390719: Marcus has two sisters. The sum of the girls' ages is 13. The product of their ages is 36. How old is each sister? \n" ); document.write( "
Algebra.Com's Answer #277098 by checkley79(3341)![]() ![]() ![]() You can put this solution on YOUR website! X+Y=13 \n" ); document.write( "X=13-Y \n" ); document.write( "XY=36 \n" ); document.write( "(13-Y)Y=36 \n" ); document.write( "13Y-Y^2=36 \n" ); document.write( "-Y^2+13Y-36=0 \n" ); document.write( "Y^2-13Y+36=0 \n" ); document.write( "(Y-9)(Y-4)=0 \n" ); document.write( "Y-9=0 \n" ); document.write( "Y=9 YEARS OLD ANS. FOR ONE SISTER \n" ); document.write( "X+9=13 \n" ); document.write( "X=13-9 \n" ); document.write( "X=4 YEARS OLD ANS. FOR THE OTHER SISTER \n" ); document.write( "Y-4=0 \n" ); document.write( "Y=4 ANS. DITTO. \n" ); document.write( "X+4=13 \n" ); document.write( "X=13-4 \n" ); document.write( "X=9 DITTO. \n" ); document.write( "PROOF: \n" ); document.write( "4+9=13 \n" ); document.write( "13=13 \n" ); document.write( "4*9=36 \n" ); document.write( "36=36 \n" ); document.write( " |