Question

4^х-3·2^х-4=0 помогите плиз

Answer 1

2^X = A ; 4 ^X = A^2 
A^2 - 3A - 4 = 0
D = 9 + 16 = 25 ; √ D = 5 
A1 = ( 3 + 5 ) : 2 = 4 
A2 = ( 3 - 5 ) : 2 = - 1 ( < 0 )
2 ^ X = 4 
2 ^ X = 2 ^ 2 
X = 2