Question

x^3+9x^2+23x+15=0 помогите срочно!

Answer 1

x^3+9x^2+23x+15=0

x^3+3x^2+6x^2+18x+5x+15=0

(x^3+3x^2)+(6x^2+18x)+(5x+15)=0

x^2(x+3)+6x(x+3)+5(x+3)=0

(x^2+6x+5)(x+3)=0

x+3=0 x=-3

X^2+6x+5=0

D=36-20=16

x1=(-6+4)/2=-1

x2=(-6-4)/2=-5

x3=-3