tolong bantu ya,, mkasihhh,, tugas penting !!

3√3/√2+√7 x √2-√7/√2-√7 =
3√6-3√21/2-7 =
3√6-3√21/-5 =
-3√6/5 + 3√21/5

= 3√3 / √2+√7 x (√2-√7) / (√2-√7)
= 3√6 - 3√21 / 2 - 7
= 3√6/-5 - 3√21/-5
=3√21/5 - 3√6/5 >> (E)