Question

0.4 la puterea 1-x>=2.5 la puterea2/x

Answer 1

DVA=R.
(4/10) ^1-x => (25/10)^2/x
(2/5)^1-x => (5/2)^2/x
(5/2)^ -1+x =>(5/2)^2/x
-1+x=>2/x
-1-2/x +x=>0
-x-2+x^2/x=>0
x^2-x-2=0
delta=9
x1=1+3/2= 2
x2=1-3/2=-1
S=(-infinit -1]  in reuniune cu [2, + infinit] /{0}.