两点间的距离是4,即|x1-x2|=4
图像经过点(2,-3),即4+2p+q=-3,2p+q=-7
x1+x2=-p
x1x2=q
(x1-x2)²=(x1+x2)²-4x1x2
4^2=p²-4q
16=p²-4(-7-2p)
16=p²+28+8p
p²+8p+12=0
(p+2)(p+6)=0
p=-2或-6.
q=-3或5
解析式为
y=x²-2x-3或y=x²-6x+5
两点间的距离是4,即|x1-x2|=4
图像经过点(2,-3),即4+2p+q=-3,2p+q=-7
x1+x2=-p
x1x2=q
(x1-x2)²=(x1+x2)²-4x1x2
4^2=p²-4q
16=p²-4(-7-2p)
16=p²+28+8p
p²+8p+12=0
(p+2)(p+6)=0
p=-2或-6.
q=-3或5
解析式为
y=x²-2x-3或y=x²-6x+5