To find the y-coordinate of the parabola described by the equation \( y = 5x^2 + 8x + 9 \) when \( x = -3 \), we can substitute \( -3 \) into the equation for \( x \):
\[ y = 5(-3)^2 + 8(-3) + 9 \]
Calculating each term step by step:
- Calculate \( (-3)^2 \):
\[ (-3)^2 = 9 \]
- Multiply by 5:
\[ 5 \times 9 = 45 \]
- Calculate \( 8(-3) \):
\[ 8 \times -3 = -24 \]
- Now substitute these values back into the equation:
\[ y = 45 - 24 + 9 \]
- Combine the terms:
\[ 45 - 24 = 21 \] \[ 21 + 9 = 30 \]
Thus, the y-coordinate of the parabola when \( x = -3 \) is:
\[ \boxed{30} \]