解一元二次方程!明天过期!2ⅹ方-3ⅹ-1=0 2y方-y-2分之1=0 4ⅹ方-6ⅹ=0

题目

解一元二次方程!明天过期!2ⅹ方-3ⅹ-1=0 2y方-y-2分之1=0 4ⅹ方-6ⅹ=0

答案

2ⅹ方-3ⅹ-1=0 x^2-1.5x-1/2=0b^2-4ac=(-1.5)^2+4*1/2=4.25x=1.5/2±√4.25/2x1=(1.5+√4.25)/2 x2=(1.5-√4.25)/22y方-y-2分之1=0 y^2-1/2*y-1/4=0(y-1/2)^2=1/2 y-1/2=±√2/2y=1/2±√2/2y1=(1+√2)/2 y2=(1-√2)...