Question

F(x)= 3x^2 + 9x. Find the roots

Answer 1

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}.

Answer 2

First, set the function to zero

`0 = x^2 + 9x`

Now factor out x

`x(3x+9)`

Now set each factor equal to zero and solve

`x=0\\3x+9=0\\3x = -9\\x = -3`

The roots are 0, -3