Question

rationalise the denominator 1/(√27-√18)

Answer 1

1/ root 27 -root 18
=1/root 27 - root 18×root 27+root 18/root 27+root 18
= root 27 + root 18/ 27 - 18

Answer 2

1/(√27-✓18)
=1/(✓27-✓18)×(✓27+✓18)/(✓27+✓18)
=✓27-✓18/✓27^2 - ✓18^2
=✓27-✓18/27-18
=✓27-✓18/9