Odpowiedź:
zad 1
1 2/5 - 1,1 * 9/11 = 1 2/5 - 11/10 * 9/11 = 1 2/5 - 9/10 = 1 4/10 - 9/10 =
= 14/10 - 9/10 = 5/10 = 1/2
liczba odwrotna do 1/2 to liczba 2
zad 2
3/(2√3 - 1) = 3/(2√3 - 1) * (2√3 + 1)/(2√3 + 1) =
= 3(2√3 + 1)/[(2√3 - 1)(2√3 + 1) = 3(2√3 + 1)/(4 * 3 - 1) =
= 3(2√3 + 1)/(12 - 1) = 3(2√3 + 1)/11
