(x^(8/9))^(1/2)*x^(5/9)=x^(8*1/(9*2)*x^(5/9)=x^(8/9)*x^(5/9)=
=x^(8/9+5/9)=x^((8+10)/18)=x^(18/18)=x¹.
(k-4)!/(k-6)!=
=(k-4)(k-5)(k-6)!/(k-6)!=
=(k-4)(k-5)/1=(k-4)(k-5)=
=kˇ2-9k+20
2x^2-x-1=0
D=b^2-4ac
D=(-1)^2-4*2*(-1)=1+8=9
√D=√9=3
x1=-b<em><u /></em><em><u />+</em>√D/2a
x1=1+3/4=1
x2=-b-√D/2a
x2=1-3/4=-0,5