1.(1.3×3.9×11.7＋3×9×27＋1/17×3/17×9/17)/(1.3×2.6×3.9＋3×6×9＋1/17×2/17×3/17)
问题描述：
1.(1.3×3.9×11.7＋3×9×27＋1/17×3/17×9/17)/(1.3×2.6×3.9＋3×6×9＋1/17×2/17×3/17)
2.2/3＋2/9＋2/27＋2/81＋2/243
3.1＋2＋3＋4＋5＋6＋7＋8＋9＋8＋7＋6＋5＋4＋3＋2＋1/999999999²
4.2×3×4×5＋5×6×7×8/2×3×4×5
5.(1＋1/2＋1/3＋1/4)×(1/2＋1/3＋1/4＋1/5)－(1＋1/2＋1/2＋1/4＋1/5)×(1/2＋1/3＋1/4)
答
1.(1.3×3.9×11.7＋3×9×27＋1/17×3/17×9/17)/(1.3×2.6×3.9＋3×6×9＋1/17×2/17×3/17)=[1.3×(1+3+9)+3×(1+3+9)+1/17 ×(1+3+9)]/[1.3×(1+2+3)+3×(1+2+3)+1/17 ×(1+2+3)]=(1.3+3+1/17)(1+3+9)/(1.3+3+1...