👤

Rezolvati ecuatiile logaritmice:

[tex] log_{3x+5} (9 x^{2} +8x+3) = 2[/tex]
[tex] log_{2} (x+2) - log_{2} (x-5) = 3[/tex]


Răspuns :

[tex]log_{3x+5}(9x^2 +8x+3)=2[/tex]
[tex]9x^2+8x+3=(3x+5)^2[/tex]
[tex]9x^2+8x+3=9x^2+25+30x[/tex]
22x=-22 => x = -1 


[tex]log_2(x+2)-log_2(x-5)=3[/tex]
[tex]log_2 \frac{x+2}{x-5} = 3[/tex]
[tex] \frac{x+2}{x-5} = 8[/tex]
x+2=8(x-5)
x = 6