Expression 11: "T" Subscript, "h" "r" "u" "s" "t" , Baseline left parenthesis, "x" , right parenthesis equals "E" Subscript, "f" "f" "i" "c" "i" "e" "n" "c" "y" , Baseline left parenthesis, "x" , right parenthesis "U" Subscript, "s" "a" "g" "e" , Baseline left parenthesis, "x" , right parenthesisThrustx=EfficiencyxUsagex