To find the roots of the polynomial function \( h(x) = 3x^2 + 243 \), we need to set the equation equal to zero:
\[ 3x^2 + 243 = 0 \]
First, we can isolate \( x^2 \):
\[ 3x^2 = -243 \]
Now, divide both sides by 3:
\[ x^2 = -81 \]
To find \( x \), take the square root of both sides:
\[ x = \pm \sqrt{-81} = \pm \sqrt{81} \cdot \sqrt{-1} \]
Since \( \sqrt{81} = 9 \) and \( \sqrt{-1} = i \), we get:
\[ x = \pm 9i \]
Thus, the roots of the polynomial function \( h(x) = 3x^2 + 243 \) are:
The roots are \( 9i \) and \( -9i \).