Solve for x in cubed polynomial equation

[randyoy]

Hi, Attempting to solver for x:

y=5/6 * x * (2x^2 +27x +91)

 

[MathLover1]

y=(5/6) x*(2x^2 +27x +91) .....factor 2x^2 +27x +91

2x^2 +27x +91
=2x^2 +14x+13x +91
=(2x^2 +14x)+(13x +91)
=2x(x +7)+13(x +7)
=(x + 7) (2 x + 13)
y=(5/6) x*(x + 7) (2 x + 13)
so, you have

set y=0

(5/6) x*(x + 7) (2 x + 13) =0

equal each factor to 0

(5/6) x =0 => x=0

(x + 7) = 0 => x=-7

(2 x + 13) =0 => x=-13/2

 

[nycmathguy]

y=(5/6) x*(2x^2 +27x +91) .....factor 2x^2 +27x +91

2x^2 +27x +91
=2x^2 +14x+13x +91
=(2x^2 +14x)+(13x +91)
=2x(x +7)+13(x +7)
=(x + 7) (2 x + 13)
y=(5/6) x*(x + 7) (2 x + 13)
so, you have

set y=0

(5/6) x*(x + 7) (2 x + 13) =0

equal each factor to 0

(5/6) x =0 => x=0

(x + 7) = 0 => x=-7

(2 x + 13) =0 => x=-13/2


View attachment 651

Nicely done.