Question

Решите уравнение х^2+21х+4=-4х^2

Answer 1

x²+21x+4= -4x²
5x²+21x+4=0

D=441-4*5*4=441-80=361

x1=-21+19/10= -2/10= -1/5
x2=-21-19/10= -40/10= -4