Interesting stuffs

1.   1/a+1/b=(a+b)/ab
Explanation:
1/a*b/b=b/ab
1/b*a/a=a/ab
a/ab+b/ab=(a+b)/ab

2.  
When x-y≥0
and y-x≥0
x=y
Explanation:
x≥y
y≥x
x=y (Only choice)