Onen way, is to know that if a=b and c=d, then a/c=b/d, and thn (a/c)(d/b)=1
the real way would be to make denomenators the same
one way would be to firs assume they are equal then show it is false 1/2=2/5 times right sides by 5/5 and left by 2/2 5/10=4/10 times 10 both sides 5=4 flase