The given expression is,
a)
Put x=4 and y=10 in expression (1) and simplify.
Therefore, when x=4 and y=10, the value of the given rational expression is 4/3.
b)
Put x=0 and y=11 in expression (1) and simplify.
Therefore, when x=0 and y=11, the value of the given rational expression is 0.