please tolong bantu nomor 13 - 17

13) √7
------------
2√3

= ( √7 )( 2√3 )
----------------------
( 2√3 )( 2√3 )

= 2√21
------------
12

= ¹/6 ( √21 )


14) 5√6
--------------
√7

= ( 5√6 )( √7 )
---------------------
( √7 )( √7 )

= 5√42
-------------
7

= 5/7 ( √42)

15) ( 3√3 + √7 )
------------------------
√7 - 2√3

= ( 3√3 + √7 )( √7 + 2√3)
--------------------------------------
( √7 - 2√3 )( √7 + 2√3 )

= 3√21 + 7 + 18 + 2√21
------------------------------------
7 - 2√21 + 2√21 - 12

= 25 + 5√21
-------------------
- 5

= 5 ( 5 + √21 )
----------------------
- 5

= - ( 5 + √21 )

= - 5 - √21

16) ( √3 - 2)( √3 + 2 )
-------------------------------
√5 - √6

= 3 - 2√3 + 2√3 - 4
------------------------------
√5 - √6

= - 1 ( √5 + √6)
-------------------------
( √5 - √6)( √5 + √6 )

= - 1 ( √5 + √6 )
-----------------------
5 - √30 + √30 - 6

= - 1 ( √5 + √6)
-----------------------
- 1

= √5 + √6

17) ( √12 - √27 )( √18 + √8)

= ( 2√3 - 3√3)( 3√2 + 2√2)

= ( - √3 )( 5√2)

= - 5√6