Question

x³+6x²+2x-3=0

Answer 1

f(x)=x^3+6x^2+2x-3
f(-1)=0
x^3+6x^2+2x-3 =(x+1)(x^2+ax-3)
coef. of x
-3+a=2
a=5
x^3+6x^2+2x-3 =0
(x+1)(x^2+5x-3)=0
x=-1 or (-5+√37)/2 or (-5-√37)/2

Answer 2

x³+6x²+2x-3=0
x³+x²+5x²+5x-3x-3=0
(x³+x²)+(5x²+5x)-(3x+3)=0
x²(x+1)+5x(x+1)-3(x+1)=0
(x+1)(x²+5x-3)=0
x+1=0
x1=-1
x²+5x-3=0
x²+5x=3
x²+5x+(5/2)²=12/4+25/4
(x+5/2)²=37/4
x+5/2=±√37/2
x=-5/2±√37/2
x2=(-5+√37)/2
x3=(-5-√37)/2