Question

Dau coroana! Am nevoie in seara asta de el rezolvat! ​

Answer 1

Răspuns:

5•2²^x-11•(2•3)^x+2•3²^x= 0

5•2²^x-11•2^x • 3^x + 2•3²^x = 0

5• (2/3)²^x - 11• (2/3)^x + 2 = 0

5• ((2/3)^x)² - 11• ( 2/3)^x + 2 = 0

5t² - 11t + 2 = 0

rezolvata cu substanta :

[ t = (2/3)^x ]

5t² - 11t + 2 = 0

t = 1/5

t = 2

(2/3)^x = 1/5

(2/3)^x = 2

x = - log 2/3 (5)

(2/3)^x = 2

x = -log 2/3 (2)

(2/3)^x = 2

x1 = log 2/3 (2) , x↓2 = -log 2/3 (5)