標題:
中四數學!!!!超急!!!!plz
發問:
用配方法解2x既2次方=7x-1 點計- -"?
2x^2 = 7x - 1 2x^2 - 7x = -1 2(x^2 - 7/2 x) = -1 2(x^2 - 7/2 x + (7/4)^2) = (7/4)^2 - 1 2(x^2 - 7/2 x + 49/16) = 49/8 - 1 2(x - 7/4)^2 = 41/8 (x - 7/4)^2 = 41/16 x - 7/4 = √(41/16) 或 x - 7/4 = -√(41/16) x - 7/4 = (√41)/4 或 x - 7/4 = -(√41)/4 x = (√41+7)/4 或 x = -(√41+7)/4
其他解答:
2x2 = 7x-1 2x2-7x+1= 0 x = {-(-7) +/- √[(-7)2-4(2)(1)]} / 2(2) x = 7/4 +/- √(41)/4 x = 0.15 or x = 3.35
中四數學!!!!超急!!!!plz
發問:
用配方法解2x既2次方=7x-1 點計- -"?
此文章來自奇摩知識+如有不便請留言告知
最佳解答:2x^2 = 7x - 1 2x^2 - 7x = -1 2(x^2 - 7/2 x) = -1 2(x^2 - 7/2 x + (7/4)^2) = (7/4)^2 - 1 2(x^2 - 7/2 x + 49/16) = 49/8 - 1 2(x - 7/4)^2 = 41/8 (x - 7/4)^2 = 41/16 x - 7/4 = √(41/16) 或 x - 7/4 = -√(41/16) x - 7/4 = (√41)/4 或 x - 7/4 = -(√41)/4 x = (√41+7)/4 或 x = -(√41+7)/4
其他解答:
2x2 = 7x-1 2x2-7x+1= 0 x = {-(-7) +/- √[(-7)2-4(2)(1)]} / 2(2) x = 7/4 +/- √(41)/4 x = 0.15 or x = 3.35
文章標籤
全站熱搜
留言列表
