x+y=600
xy=67
x*(600-x) -67=0
-x^ +600x-67=0
or x^2 -600x +67=0
quadrateik equashun giv x=599.8883125 or 0.1116875
############## me thank yu got the 2 numbers bakwards so it shood be
xy=600 & x+y=67, so yu get x^2 -67x +600=0
then yu get roots=10.6472102 or 56.3527898