Using the numbers [4, 1, 3, 9], create an equation that equals 67. You can use basic arithmetic operations (+, -, *, /) and each number can only be used once. Show your work in <think> </think> tags. And return the final equation and answer in <answer> </answer> tags, for example <answer> (2 + 2) * (3 * 7) = 67 </answer>.