Q.5. Rationalise the denominators of the following:

i17          ii17-6

iii15+2         iv17-2

Solution:

i 17=17×77=77

ii17-6=17-6×7+67+6

=7+67-6=7+6 

iii15+2=15+2×5-25-2

=5-25-2=5-23 

iv 17-2=17-2×7+27+2

=7+27-4=7+23