Question

Решите уравнение: 2) x^2 + 9 + 6x = 0; 3) 4x^2 = 9; 4) 4x^2 + 16x = 9; 5) x^2 + 4x - 5 = 0.

Answer 1

2)x^2+9+6x=0 x^2+6x+9=0 D=36-36=0 x1=-6+0/2=-3 
3) 4x^2=9  2x=3 x=3/2  x1=1,5 x2=-1,5
4)4x^2+16x-9=0 D=256+144=400=20 x1=-16+20/8=0,5 x2=-16-20/8=-4/5
5)x^2+4x-5=0  x1+x2=-b/a x1*x2=c/a x1=-5 x2=1