2/5 =
1/5
1/2
4/10
4/5
2/5
x/y
2x + 3
2x - 3
x2/y2
Multiplicative inverse of 7/9 is
1
0
9/7
14/18
x(x - 1)
x (x + 1)
(x + 1) (x - 1)
x - 1