Question

Fie numerele strict pozitive x-1, x, x+3 in progresia geometrica. Sa se determine x.

Answer 1

$\displaystyle x-1,~x,~x+3~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ \boxed{b^2=a \cdot c} \\ x^2=(x-1)(x+3) \\ x^2=x^2+3x-x-3 \\ x^2-x^2-3x+x=-3 \\ -2x=-3 \\ x= \frac{3}{2}$