4
√3(√3-a)/(a-√3)(a+√3)=-√3/(a+√3)
6
(√x-√y)(√x+√y)/(√x+√y(-(√x+2√y)²/(√x+2√y)=√x-√y-√x-2√y=-3√y
x=3 1/81,y=1/81
-3*1/9=-1/3
8
y√x²=y*|x|=(3+√11)*|3-√11)=(3+√11)*(√11-3)=11-9=2
9
1)a/(a-√2(-√2/(a+√2)=(a√=a√2-a√2+2)/(a²-2)=(a²+2)/(a²-2)
2)(a²+2)/(a²-2):(a²+2)/(a²=a²2)=(a²=2)/(a-√2)(a+√2) *a(a+√2)/(a²+2)=a/(a-√2)