[latex]displaystyle Fie~f,g: mathbb{R} o mathbb{R},~f(x)=3^x+4^x~si~g(x)=8-x. \ \ Observam~ca~f~este~strict~crescatoare,~iar~g~este~strict \ \ descrescatoare. \ \ Prin~urmare~ecuatia~f(x)=g(x)~admite~cel~mult~o~solutie, \ \ si~cum~x=1~este~solutie,~aceasta~este~unica~solutie~a~ecuatiei \ \ date.[/latex]