Question

sa se rezolve: $3 ^{x} +4 ^{x}= 7^{x}$

Answer 1

[tex]Se~observa~ca~x=1~este~solutie~pentru~ecuatie.\\ 3^x+4^x=7^x|:7^x\\ ( \frac{3}{7} )^x+( \frac{4}{7} )^x=1\\ Functia~f(x)=( \frac{3}{7} )^x+( \frac{4}{7} )^x~este strict~ ~descrescatoare.\\ Concluzie:x=1~este~ singura~solutie~reala. [/tex]