P If three real and distinct numbers \( a, b, c \) are in G.P. (i.e...

P
If three real and distinct numbers \( a, b, c \) are in G.P. (i.e., \( b^{2}=a c \) ) and \( a+b+c=x b \), then prove that \( x \)
W \( -1 \) or \( \mathrm{x}3 \).