I just need you to calculate R= ?

b-2. What is the dollar-weighted rate of return? (Hint: If your calculator cannot calculate internal rate of return, you will have to use a spreadsheet or trial and error.) (Negative value should be indicated by a minus sign. Round your answer to 4 decimal places.) The dollar-weighted average return is the IRR of the cash flows provided in the above chart.

-496+(-389)/(1+r)+143/((1+r)^2)+744/((1+r)^3)=0

r =