First, set the function to zero
[tex]0 = x^2 + 9x[/tex]
Now factor out x
[tex]x(3x+9)[/tex]
Now set each factor equal to zero and solve
[tex]x=0\\3x+9=0\\3x = -9\\x = -3[/tex]
The roots are 0, -3
F(x)= 3x^2 + 9x can be factored: F(x)= 3x(x + 3). Setting this = to 0, we get x = 0 and x = -3. The roots are {-3, 0}.
