Question

Sa se determine x aprtine R,stiind ca numerele x-1,x+1 si 2x+5 sunt termeni consecutivi ai unei progresii geometrice.

Answer 1

$(x+1)^2=(x-1)(2x+5)$
$x^{2} +2x+1=2 x^{2} +5x-2x-5$
$x^{2} +x-6=0$
$x=-3$
$x=2$