if 12 : 18 : : x : 9 , then find the value of x
explanation : treat 12 : 18 as 12 / 18 and x : 9 as x / 9 , treat : : as = so we get 12 / 18 = x / 9 = > 18 x = 108 = > x = 6 option c
divide(add(multiply(18, 12), 18), 9)