✨ 最佳解答 ✨ delta 約1年以前 =1.7×3×1.03+4.9×1.03+1.7 =5.1×1.03+4.9×1.03+1.7 =1.03(5.1+4.9)+1.7 =1.03×10+1.7 =10.3+1.7 =12 留言