Part $1$: What is the IRR of the set of cash flows? $($Pictured below$)$

Part $2$:

For the following set of cash flow: Year $0$: Cash flow:$-$$$8309,$ Year $1$: Cash Flow: $$6,000,$ Year $2$: Cash Flow:$$3,400,$ Year $3$: Cash Flow: $$5,700.$ A$.$ What is the NPV at a discount rate of $0$ percent? B$.$ What is the NPV at a discount rate of $11\%$ C$.$ What is the NPV at a discount rate of $20\%$ D$.$ What is the NPV at a discount rate of $25\%?$