Question

Rezolvati, in multimea numerelor reale, ecuatia: radical in baza 3 (1+7x)=1+x

Answer 1

ec. din enunt <=> 1+7x=(1+x)^3 <=>1+7x=x^3+3x^2+3x+1 <=> x^3+3x^2-4x=0 <=> x(x^2+3x-4)=0 <=> x(x-1)(x+4)=0 <=> x=0 sau x=1 sau x=-4.