Question

Решите через дискриминант: 2x^2+x-21= -8x^2

Answer 1

2x²+x+8x²-21=0
10x²+x-21=0
D=1+840=841
x1=-1+29\2=28\2=14
x2=-1-29\2=-30\2=-15

Answer 2

2 х^2+8x^2+x-21=0
10x^2+x-21=0
D=1+4*10*21=1+840=841=29^2
x1=(-1+29)/20=28/20=1.4
x2=(-1-29)/20=-30/20=1.5
x=(-b-(+)√D)/2a