# [Brain-Flak], <s>158</s> 154 bytes

    (({}<>)(([()()()]){}<>)<({}[()()()]({}))([((()()()){}){}]{((()()()){}){}(<{}>)}{})>)([()]{()(<{}>)}{})({<{}>{}((<()>))}<{}{}>{<({}[()])><>({})<>}{}<><{}>)

[Try it online!][TIO-j3gd3s9s]

[Brain-Flak]: https://github.com/DJMcMayhem/Brain-Flak
[TIO-j3gd3s9s]: https://tio.run/##VY0xCoRQDET7PclMYSsIIReRX2ghyIqF7Sdn/07cFZGkmDeZMPMxrXu3bNO3NaCGOYERzCm82GTfjiSpO36sgLbUN8NqOEPaM0vd@XioKZWCQQGGMI1/TaGbZ415ZP3111r/GU4 "Brain-Flak – Try It Online"
# Explanation

This code is pretty simple.  We make copies of the top two items on the stack, we subtract 6 from one and 9 from the other.  We then take the not of the two values.  We and those values, multiply the result by 12.  Multiply the inputs and subtract the two results.