Find the values of a and b such that the function f defined by following function is a continuous function at x = 4.

So, \[-1\text{ }+\text{ }a\text{ }=\text{ }a\text{ }+\text{ }b\text{ }=\text{ }1\text{ }+\text{ }b\]

\[-1\text{ }+\text{ }a\text{ }=\text{ }a\text{ }+\text{ }b\text{ }and\text{ }1\text{ }+\text{ }b\text{ }=\text{ }a\text{ }+\text{ }b\]

We get, \[b\text{ }=\text{ }-1\text{ }and\text{ }1\text{ }+\text{ }-1\text{ }=\text{ }a\text{ }+\text{ }-1\Rightarrow a\text{ }=\text{ }1\]

Therefore, the value of \[a\text{ }=\text{ }1\text{ }and\text{ }b\text{ }=\text{ }-1\]