2x²+6=7x怎么接配方法
问题描述：
2x²+6=7x怎么接
配方法
答
2x² + 6 = 7x
2x² - 7x + 6 = 0
x² - (7 / 2) x + 3 = 0
x² - (7 / 2) x + (7 / 4) ² - (7 / 4) ² + 3 = 0
( x - 7 / 4 ) ² - 49 / 16 + 48 / 16 = 0
( x - 7 / 4 ) ² - 1 / 16 = 0
( x - 7 / 4 ) ² = 1 / 16
x - 7 / 4 = ± 1 / 4
x = ± 1 / 4 + 7 / 4
x1 = 1 / 4 + 7 / 4 = 8 / 4 = 2
x2 = - 1 / 4 + 7 / 4 = 6 / 4 = 3 / 2
答
2x²+6=7x
2x²-7x+6=0
(x - 2) (2x - 3) = 0
x = 2 or x = 1.5
答
2x²+6=7x
2x²-7x=-6
2x²-7x+49/2=-6+49/2
2(x-7/2)²=37/2
(x-7/2)²=37/4
所以
x-7/2=±√37/2
得
x=(7±√37)/2