Ex: Derivative Application - Minimize Cost

[@johnnychin9598]

can you show an example to get the function of x =3.5x +9000x+6000. where and how do you get those equation. how can we formulate those equation in real world scenario. all the teaching of calculus in youtube shows something to calculate like that wherein how do we get that function in the first place. i feel this kind of teaching is alittle bit unrealistic. i wish you can give example from scratch wherein you lay down the problem, you formulate those function base from the problem and you use calculus to solve it.