解ï¼
5ã
y²+3y+1=0
y²+3y+(3/2)²-9/4+1=0
(y+3/2)²-5/4=0
(y+3/2)²-(â5/2)²=0
(y+3/2+â5/2)(y+3/2-â5/2)=0
y+3/2+â5/2=0æy+3/2-â5/2=0
y1=-(3+â5)/2 y1=-(3-â5)/2
6ã
3x²-9x+2=0
x²-3x+2/3=0
x²-3x+(3/2)²-9/4+2/3=0
(x-3/2)²-19/12=0
(x-3/2)²-(â19/12)²=0
(x-3/2+â57/6)(x-3/2-â57/6)=0
x-3/2+â57/6=0æx-3/2-â57/6=0
x1=(9-â57)/6 x2=(9+â57)/6