1.x²-x-6=0
(x-3)(x+2)=0
x=3或x=-2
2.y²-5y-14=0
(y-7)(y+2)=0
y=7或y=-2
3.(2m-1）²-3（2m-1)+2=0
(2m-1-2)(2m-1-1)=0
2(2m-3)(m-1)=0
m=1或m=3/2