Question

如图,数轴上与根号3,根号5对应的点分别是A,B,点B关于点A的对称点为C,设点C表示的数为X.

Answer 1

x=根3-(根5-根3)=2根3-根5
(17+4根15)x²-(2根3+根5)x-2
=(17+4根15)(12-4根15+5)-(2根3+根5)(2根3-根5)-2
=289-240-(12-5)-2
=49-7-2
=40

Answer 2

√3-x=√5-√3
∴x=2√3 -√5

2、(17+4√15)x²-(2√3+√5)x-2
=(17+4√15)(2√3-√5)² -(2√3+√5)(2√3-√5)-2
=(17+4√15)(17-4√15)-(12-5)-2
=289-240-7-2
=40