Question

Aflati x ∈ R, stiind ca:
a) x+1, x-1, sunt consecutivi intr-o progresie aritmetica
b) x-1, x+1, 2x+5 intr-o progresie geometrica

Answer 1

 a)x+1x−1=x+x+−1
=x+x+−1=(x+x)+(−1)=2x+−1
=2x−1