國中數學急，求解，…........?
回答 (1)
2020-08-27 3:55 pm
a□EBFD = a△BED + a△DBF
= (1/2)(3x+5)(2x+1) + (1/2)(5x-3)(2x-5)
= (1/2)(6x^2+13x+5) + (1/2)(10x^2-31x+15)
= (1/2)(16x^2-18x+20)
= 8x^2 - 9x + 10
= (1/2)(3x+5)(2x+1) + (1/2)(5x-3)(2x-5)
= (1/2)(6x^2+13x+5) + (1/2)(10x^2-31x+15)
= (1/2)(16x^2-18x+20)
= 8x^2 - 9x + 10
收錄日期: 2021-04-24 07:57:37
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20200827041412AAE9CiT