19 - 9√5 / -11 = (- 19 + 9√5 )/11
so a = 9
and b = -19
it is easy , right ?

why to rationalise
The main reason we tell students to do this is to have a standard form
in which certain kinds of answers can be written. That makes it
easier for us as teachers to check the answers, and for the students
to check their own answers in their book. Also, putting things in a
standard form can make it easier to recognize similar forms in a
complicated problem, and to combine them. For example, if you had to
add sqrt(5) and 1/sqrt(5), you would not see that they can be combined
until you chan
no need to rationalise as it does not have a negative symbol
What do you mean ?
rationalising it gives -1/29