9^(x+1) + 3 >= 28 * 3^x

Chto nam s etim robit???

9^(x+1) + 3 >= 28 * 3^x
3^x=t
9t²-28t+3≥0
D=784-108=676
t12=(28+-26)/18=1/9 3
9(t-1/9)(t-3)≥0
======1/9==========3=======
++++++    -------------      +++++
3^x<=1/9
x<=-2
3^x>=3
x>=1
x=(-oo -2]U[1 +oo)