Question

Rezolvați in multimea nr reale ecuatia 2^(2x+3)-3*2^(x+2)+4=0

Answer 1

2³ *2^2x-3*2² *2^x+4=0
8*2^2x-12*2^x+4=0
2^x=y
8y²-12y+4=0
2y²-3y+1=0

y1,2= [3+-√(9-8)]/2*2= (3+-1)/4
y1=1/2 
2^x=1/2  x=-1

y2=1 
2^x=1
x=0


verificare pt x=0..8-12+4=0
pt x=-1....2-6+4=0
adevarat ,problema e bine rezolvata