t>0
9^(x)=t^2
[m]\frac{13-5t}{t^2-12t+27}\geq \frac{1}{2}[/m]
[m]\frac{13-5t}{t^2-12t+27}-\frac{1}{2} \geq 0[/m]
[m]\frac{26-10t-t^2+12t-27}{2\cdot (t^2-12t+27)} \geq 0[/m]
[m]\frac{-t^2+2t-1}{2\cdot (t^2-12t+27)} \geq 0[/m]
[m]\frac{(t-1)^2}{2\cdot (t^2-12t+27)} \leq 0[/m]
[m]\frac{(t-1)^2}{2\cdot (t-3)(t-9)} \leq 0[/m]
___+_ [1] __+__ (3) ____-___ (9) ___+____
t=1 или 3<t<9
3^(x)=1 или 3 < 3^(x) < 3^2
x=0 или 1< x < 2
О т в е т. {0}U(1;2)