👤

3 la puterea x - 4 la puterea x = radical din ( 12 la puterea x - 16 la puterea x )

Răspuns :

3ˣ-4ˣ=√(3·4)ˣ-4²ˣ
3ˣ-4ˣ=√4ˣ(3ˣ-4ˣ)  facem ridicarea la putere 
(3ˣ-4ˣ)²=4ˣ(3ˣ-4ˣ)
3²ˣ-2· 3ˣ ·4ˣ+4²ˣ=4ˣ· 3ˣ-4²ˣ se imparte la 4ˣ· 3ˣ
(3/4)ˣ-2+(4/3)ˣ=1-(4/3)ˣ
(4/3)ˣ=y
1/y-2+y=1-y
2y²-3y+1=0
Δ=9-8=1
√Δ=√1=1
y₁=1
y₂=1/2

(4/3)ˣ=y₁
(4/3)ˣ=1
(4/3)ˣ=(4/3)⁰
x=0

(4/3)ˣ=y₂
(4/3)ˣ=1/2