Rezolvati ecuatia:

4ˣ+4=5 × 2ˣ


Răspuns :

[tex] 2^{2} totul.la.x +4=5* 2^{x} [/tex]
[tex] 2^{2x} -5* 2^{x} +4=0 [/tex]
Notam : [tex] 2^{x} [/tex] = t , t>0
[tex] t^{2} -5t+4=0[/tex] => Δ = 9
[tex] t_{1} = \frac{5+3}{2} = 4[/tex]
[tex] t_{2} = \frac{5-3}{2} = 1[/tex]

pt t=4 => [tex] 2^{x} = 4[/tex] => x=2
pt x=1 => [tex] 2^{x} = 1[/tex]=> x=0