Cat face 2 la puterea x-1 + 2 la puterea x = 12 ? Va rog sa fiti expliciti

Răspuns :

2^(x-1) + 2^x = 12 
2^x ( 2^-1 + 1) = 12 
2^x × 3/2  = 12 
2^x = 12 : 3/2 
2^x = 8
2^x = 2^3 
x = 3  
2ˣ⁻¹+2ˣ=12
2ˣ(2⁻¹ + 1)=12
2ˣ(1/2 +1)=12
2ˣ x 3/2 =12
2ˣ = 12 : 3/2= 12 x 2/3 =8
2ˣ=8=2³⇒ x=3