Đáp án:
$1) x²+2(m-1)+m=0$
$Δ=b²-4ac $
$= [2(m-1)]²-4.1.m$
$= 4(m²-2m+1)-4m$
$= 4m²-8m+4-4m$
$= 4m²-12m+4$
$2) -4x²-2(m+1)+2m-1=0$
$Δ=b²-4ac$
$= [-2(m+1)]²-4.(-4).(2m-1)$
$= 4(m²+2m+1)+16(2m-1)$
$= 4m²+8m+4+32m-16$
$= 4m²+40m-12$
$3) 5x²+(m-3)x+2m+1=0$
$Δ=b²-4ac$
$= (m-3)²-4.5.(2m+1)$
$= m²-6m+9 - 20(2m+1)$
$= m²-6m+9-40m-20$
$= m²-46m - 11$
$4) mx²-2(m-3)x+5=0$
$Δ=b²-4ac$
$= [-2(m-3)]²-4m.5$
$= 4(m²-6m+9)-20m$
$= 4m²-24m+36-20m$
$= 4m²-44m+36$
$5) -x²+(2m-1)x+m²-4m+9=0$
$Δ=b²-4ac$
$= (2m-1)²-4.(-1).(m²-4m+9)$
$= 4m²-4m+1+4(m²-4m+9)$
$= 4m²-4m+1+4m²-16m+36$
$= 8m²-20m+37$
BẠN THAM KHẢO NHA!!!