解方程(2x-1)^2-7=3(x+1)【速度】
问题描述:
解方程(2x-1)^2-7=3(x+1)【速度】
RT.
一定确定正确.
用配方法和因式分解都算算,我怎么算怎么算不对.
答
(2x-1)" -7 = 3(x+1)4x" -4x +1 -7 = 3x +34x" -7x -9 =0配方计算,就是x" -(7/4)x =(9/4)x" - 2(7/8)x +(7/8)" = 144/64 +49/64(x - 7/8)" = 193/64x - 7/8 = 正负(根号193) /8x1 = 7/8 +(根号193)/8 = (7+ 根号193)...