Expression 5: "y" Subscript, 1 , Baseline tilde StartFraction, left parenthesis, "P" times "x" Subscript, 1 , Baseline , right parenthesis Over left parenthesis, "K" plus "x" Subscript, 1 , Baseline , right parenthesis , EndFraction minus "r"y1~P·x1K+x1−r