&#92；[ &#92；text{IRR} = &#92；frac{(F&#92；text{IRR} - i_1)}{(i_2 - i_1)} = &#92；frac{&#92；text{NPV}_1}{&#92；left| &#92；text{NPV}_1 &#92；right| &#92；left| &#92；text{NPV}_2 &#92；right|} &#92；]。2.年金现值系数可以先计算。&#92；[ &#92；left( &#92；frac{p}{A}.&#92；text{FIRR}.n &#92；right) = &#92；frac{K}{R} &#92；]。3.查看年金现值系数表，找出与年金现值系数相邻的两个系数。