Question

I'm in a college economics class and I'm really struggling. Can someone please explain
MPC = Supply
MSC>MPC
MSC = Supply + Spillover cost
Without intervention market determines output at *q
With intervention, socially desirable output at Qs.
CORRECTING FOR NEGATIVE EXTERNALITIES
Since MSC>MPC, the solution is to raise the MPC
Tax the product
Tax = Ps-Pt
Ps=Social optimal price
Pt= MPC at Qs
Tax revenues from the tax =per unit tax
Qs=Number of Units taxed
Tax Revenues=Qs (Ps-Pt)

Thank you so much!