Question

URGENT
Cine ma poate ajuta la exercitiile din poza (ecuatii exponentiale)?
Dau coroana!
Multumesc in avans!

Answer 1

1) fie $2^{x}=t,t\ \textgreater \ 0 \\ t^{2}-6t+8=0;t=2;t=4$
revenim la substitutie si obtinem x=1 si x=2
2)fie$( \frac{1}{4} )^{x}=a,a\ \textgreater \ 0 \\ 4 a^{2}+15a-4=0;a=-4;a=- \frac{1}{4}$
deci ecuatia nu are solutii reale
3)$2^{x}= 3^{x};( \frac{2}{3})^x=1;x=0$
4)$3* 4^x+6^x-2*9^x=0 \\ impartim .la.4^x \\ 3+(\frac{3}{2})^x-2*( \frac{3}{2}) ^{2x}=0 \\ notam . (\frac{3}{2})^x=t \\ -2 t^{2}+t+3=0;t= \frac{3}{2} \\ revenind ;la;substitutie;x=1$