1) (а-64) (√а - 8)(√а + 8)
-------------- = ------------------------ =√а + 8
(√а - 8) √а - 8
2) √11-11 √11*(1-√11)
----------- = ------------------ = 1 - √11
√11 √11
3) а-5 (√а)²-(√5)² (√а- √5 )(√а+ √5)
-------------- = ------------------------ = ------------------------- = √а -√5
а+2√5а+5 (√а)²+2√5а+(√5)² (√а+√5)