ωǒ璦yōu╋

Given that x^2-2x-5=0 has 2 different roots，andx^2+ax+b=0 has 2roots，each 2 less than the corresponding root of the equation， find the values of a and b.

唔該識解的你，可不可以花1min幫我解.
解數送100蚊vlan錢.

[ 本帖最後由 ωǒ璦yōu╋ 於 2013-5-22 21:10 編輯 ]

ωǒ璦yōu╋

Hint ，if the roots of x^2-2x-5=0 are ath and bate,the roots of the second quadratic eqution will be ath-2and -2.
佢比我呢呢個hint

ωǒ璦yōu╋

引用:

原帖由 EsCapE.gag2 於 2013-5-22 22:39 發表
岩岩問完我今年考des既表哥

佢話當頭1條equation個2個roots係c同d 第2條equation既roots係c'同d'

所以知道c+d=2同cd=-5

題目話c'=c-2同d'=d-2

咁c'+d'=c+d-4=-2

咁c'd'=(c-2)(d-2)=cd-2(c+d)+4=-5

所以第2條式 ...

對啦，多謝你.