3) √(11- 6√2) +√(33 -20√2) +√(19 -6√2) = √(3- √2)² +√(5 -2√2)² +√(3√2 -1)² =
(3- √2) + (5 -2√2) +√(3√2 -1) = 7.
5) ( (√a/(√a- 2) -a/((√a)³ +2³)* (a-2√a+4)/(√a-2)) : 8/(√a - 2)² -(a+√a+6)/4(√a+2) =
( (√a/(√a- 2) -a/(√a +2)(√a-2))*(√a - 2)² /8) - (a+√a+6)/4(√a+2) =( (√a(√a+2) -a)/(√a +2)(√a-2))*((√a - 2)² /8 - (a+√a+6)/4(√a+2) =2√a *(√a - 2)/8(√a +2) - (a+√a+6)/4(√a+2) =
√a *(√a - 2)/4(√a +2)- (a+√a+6)/4(√a+2) =(a - 2√a - a -√a -6)/4(√a+2) = -3(√a+2)/4(√a+2)
= - 3/4 * * * = -0.75 * * *