Question

x/(x/12+x/15)*(x/12-x/15)=60

Answer 1

X/X×（1/12+1/15）×X×（1/12-1/15）=60

X/X×9/60×X×1/60=60

X/9X/60×X/60=60

X×60/9X×X/60=60

60/9×X/60=60

X/9=60

X=60×9

X=540