Question

x^2+mx-1=0 和2x^2;-mx+3x-5=0这两个方程只有一个相同的实数根 求m的值和这个方程的根?

Answer 1

x^2+mx-1=0 两根A,B ; 2x^2-(m-3)x-5=0两根A,C ;B≠C

A+B=-m;AB=-1 ; A+C=(m-3)/2 ;AC=-5/2 => B/C=2/5 LET B=2K;C=5K

=>A+2K=-m;A+5K=(m-3)/2 => 3K=(3m-3)/2 => K=(m-1)/2 ;A=-2m+1

=>A=-2m+1,B=m-1;C=5(m...